Document And Entity Information - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Feb. 23, 2016 |
Jun. 30, 2015 |
|
| Document Information [Line Items] | |||
| Entity Registrant Name | Great Plains Energy Inc | ||
| Entity Central Index Key | 0001143068 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity Well-known Seasoned Issuer | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Filer Category | Large Accelerated Filer | ||
| Entity Public Float | $ 3,725,295,076 | ||
| Entity Common Stock, Shares Outstanding | 154,414,902 | ||
| Document Fiscal Year Focus | 2015 | ||
| Document Fiscal Period Focus | Q4 | ||
| Document Type | 10-K | ||
| Amendment Flag | false | ||
| Document Period End Date | Dec. 31, 2015 |
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- Definition If the value is true, then the document is an amendment to previously-filed/accepted document. No definition available.
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- Definition End date of current fiscal year in the format --MM-DD. No definition available.
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- Definition This is focus fiscal period of the document report. For a first quarter 2006 quarterly report, which may also provide financial information from prior periods, the first fiscal quarter should be given as the fiscal period focus. Values: FY, Q1, Q2, Q3, Q4, H1, H2, M9, T1, T2, T3, M8, CY. No definition available.
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- Definition This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD. No definition available.
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- Definition The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word "Other". No definition available.
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- Definition A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument. No definition available.
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- Definition Indicate "Yes" or "No" whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure. No definition available.
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- Definition Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, (4) Smaller Reporting Company (Non-accelerated) or (5) Smaller Reporting Accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No definition available.
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- Definition State aggregate market value of voting and non-voting common equity held by non-affiliates computed by reference to price at which the common equity was last sold, or average bid and asked price of such common equity, as of the last business day of registrant's most recently completed second fiscal quarter. The public float should be reported on the cover page of the registrants form 10K. No definition available.
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- Definition The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Indicate "Yes" or "No" if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. No definition available.
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- Definition Indicate "Yes" or "No" if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A. No definition available.
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- Definition Includes equity component of Allowance for Funds Used During Construction and the aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items. No definition available.
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- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Cost incurred for transmission operations and maintenance by total kilowatt-hours paid to sources other than affiliates. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Total costs of sales and operating expenses for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. No definition available.
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- Definition The aggregate revenue, whether regulated or unregulated, derived from the generation, transmission and distribution of electricity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of the cost of borrowed funds accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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- Definition Amount after tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of tax expense (benefit) related to (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount before tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax of reclassification adjustment from accumulated other comprehensive (income) loss related to net period benefit cost (credit) for pension and other postretirement defined benefit plans. No definition available.
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- Definition The sum of expenses not otherwise specified in the taxonomy for managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate amount of other expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating expense recognized during the period. Such amounts may include: (a) unusual costs, (b) loss on foreign exchange transactions, (c) losses on securities (net of profits), and (d) miscellaneous other expense items. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders. No definition available.
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- Definition All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of operating expense for fuel used by regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of operating expense for routine plant maintenance, repairs and operations of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of operating expense for purchased power of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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Consolidated Balance Sheets - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
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|---|---|---|---|---|---|---|---|---|---|---|---|
| Current Assets | |||||||||||
| Cash and cash equivalents | $ 11.3 | $ 13.0 | |||||||||
| Funds on deposit | 2.1 | 1.2 | |||||||||
| Receivables, net | 147.7 | 160.3 | |||||||||
| Accounts receivable pledged as collateral | 175.0 | 171.0 | |||||||||
| Fuel inventories, at average cost | 118.4 | 90.1 | |||||||||
| Materials and supplies, at average cost | 155.7 | 152.7 | |||||||||
| Deferred refueling outage costs | 19.2 | 12.5 | |||||||||
| Refundable income taxes | 3.8 | 3.1 | |||||||||
| Deferred income taxes | 0.0 | 78.1 | |||||||||
| Prepaid expenses and other assets | 31.0 | 36.9 | |||||||||
| Assets, Current, Total | 664.2 | 718.9 | |||||||||
| Utility Plant, at Original Cost | |||||||||||
| Electric | [1] | 13,189.9 | 12,128.7 | ||||||||
| Less-accumulated depreciation | 4,943.7 | 4,828.3 | |||||||||
| Net utility plant in service | 8,246.2 | 7,300.4 | |||||||||
| Construction work in progress | 347.9 | 900.0 | |||||||||
| Nuclear Fuel, Net of Amortization | 68.3 | 79.2 | |||||||||
| Public Utilities, Property, Plant and Equipment, Net | 8,662.4 | 8,279.6 | |||||||||
| Investments and Other Assets | |||||||||||
| Nuclear decommissioning trust fund | 200.7 | 199.0 | |||||||||
| Regulatory Assets | 979.1 | 1,034.6 | |||||||||
| Goodwill | 169.0 | 169.0 | |||||||||
| Other Assets, Noncurrent | 63.2 | 52.3 | |||||||||
| Investments and Other Assets, Total | 1,412.0 | 1,454.9 | |||||||||
| Assets, Total | 10,738.6 | 10,453.4 | |||||||||
| Current Liabilities | |||||||||||
| Notes payable | 10.0 | 4.0 | |||||||||
| Collateralized note payable | 175.0 | 171.0 | |||||||||
| Commercial paper | 224.0 | 358.3 | |||||||||
| Current maturities of long-term debt | 1.1 | 15.1 | |||||||||
| Accounts payable | 352.9 | 388.0 | |||||||||
| Accrued taxes | 31.6 | 30.4 | |||||||||
| Accrued interest | 44.7 | 41.3 | |||||||||
| Accrued compensation and benefits | 41.4 | 35.2 | |||||||||
| Pension and post-retirement liability | 3.4 | 2.8 | |||||||||
| Other Liabilities, Current | 31.6 | 24.7 | |||||||||
| Liabilities, Current, Total | 915.7 | 1,070.8 | |||||||||
| Deferred Credits and Other Liabilities | |||||||||||
| Deferred income taxes | 1,158.8 | 1,089.7 | |||||||||
| Deferred tax credits | 125.1 | 126.0 | |||||||||
| Asset retirement obligations | 275.9 | 195.9 | |||||||||
| Pension and post-retirement liability | 455.2 | 508.6 | |||||||||
| Regulatory liabilities | 284.4 | 282.7 | |||||||||
| Other Liabilities, Noncurrent | 82.9 | 88.9 | |||||||||
| Liabilities, Noncurrent, Total | 2,382.3 | 2,291.8 | |||||||||
| Common shareholders' equity | |||||||||||
| Common Stock, Value, Issued | 2,646.7 | 2,639.3 | |||||||||
| Retained earnings | 1,024.4 | 967.8 | |||||||||
| Treasury Stock, Value | (2.6) | (2.3) | |||||||||
| Accumulated other comprehensive loss | [2] | (12.0) | (18.7) | ||||||||
| Common Shareholders' Equity, Total | 3,656.5 | 3,586.1 | |||||||||
| Cumulative preferred stock $100 par value | |||||||||||
| Preferred Stock, Value, Issued | 39.0 | 39.0 | |||||||||
| Long-term debt | [3] | 3,745.1 | 3,465.7 | ||||||||
| Total Capitalization | $ 7,440.6 | $ 7,090.8 | |||||||||
| Commitments and Contingencies | |||||||||||
| Liabilities and Equity, Total | $ 10,738.6 | $ 10,453.4 | |||||||||
| Preferred Stock 3 Point 80 [Member] | |||||||||||
| Cumulative preferred stock $100 par value | |||||||||||
| Preferred Stock, Value, Issued | 10.0 | 10.0 | |||||||||
| Preferred Stock 4 Point 50 [Member] | |||||||||||
| Cumulative preferred stock $100 par value | |||||||||||
| Preferred Stock, Value, Issued | 10.0 | 10.0 | |||||||||
| Preferred Stock 4 Point 20 [Member] | |||||||||||
| Cumulative preferred stock $100 par value | |||||||||||
| Preferred Stock, Value, Issued | 7.0 | 7.0 | |||||||||
| Preferred Stock 4 Point 35 [Member] | |||||||||||
| Cumulative preferred stock $100 par value | |||||||||||
| Preferred Stock, Value, Issued | 12.0 | 12.0 | |||||||||
| Kansas City Power and Light Company [Member] | |||||||||||
| Current Assets | |||||||||||
| Cash and cash equivalents | 2.3 | 2.7 | |||||||||
| Funds on deposit | 0.5 | 0.6 | |||||||||
| Receivables, net | 129.2 | 128.9 | |||||||||
| Related party receivables | 65.8 | 68.8 | |||||||||
| Accounts receivable pledged as collateral | 110.0 | 110.0 | |||||||||
| Fuel inventories, at average cost | 83.5 | 58.8 | |||||||||
| Materials and supplies, at average cost | 114.6 | 110.1 | |||||||||
| Deferred refueling outage costs | 19.2 | 12.5 | |||||||||
| Refundable income taxes | 79.0 | 57.5 | |||||||||
| Deferred income taxes | 0.0 | 5.0 | |||||||||
| Prepaid expenses and other assets | 27.1 | 32.7 | |||||||||
| Assets, Current, Total | 631.2 | 587.6 | |||||||||
| Utility Plant, at Original Cost | |||||||||||
| Electric | [4] | 9,640.4 | 8,737.3 | ||||||||
| Less-accumulated depreciation | 3,722.6 | 3,658.7 | |||||||||
| Net utility plant in service | 5,917.8 | 5,078.6 | |||||||||
| Construction work in progress | 246.6 | 791.2 | |||||||||
| Nuclear Fuel, Net of Amortization | 68.3 | 79.2 | |||||||||
| Public Utilities, Property, Plant and Equipment, Net | 6,232.7 | 5,949.0 | |||||||||
| Investments and Other Assets | |||||||||||
| Nuclear decommissioning trust fund | 200.7 | 199.0 | |||||||||
| Regulatory Assets | 732.4 | 745.7 | |||||||||
| Other Assets, Noncurrent | 17.6 | 13.8 | |||||||||
| Investments and Other Assets, Total | 950.7 | 958.5 | |||||||||
| Assets, Total | 7,814.6 | 7,495.1 | |||||||||
| Current Liabilities | |||||||||||
| Collateralized note payable | 110.0 | 110.0 | |||||||||
| Commercial paper | 180.3 | 358.3 | |||||||||
| Current maturities of long-term debt | 0.0 | 14.0 | |||||||||
| Accounts payable | 258.8 | 305.2 | |||||||||
| Related party payables | 0.0 | 12.6 | |||||||||
| Accrued taxes | 25.6 | 23.6 | |||||||||
| Accrued interest | 32.4 | 29.0 | |||||||||
| Accrued compensation and benefits | 41.4 | 35.2 | |||||||||
| Pension and post-retirement liability | 2.0 | 1.5 | |||||||||
| Other Liabilities, Current | 12.6 | 12.4 | |||||||||
| Liabilities, Current, Total | 663.1 | 901.8 | |||||||||
| Deferred Credits and Other Liabilities | |||||||||||
| Deferred income taxes | 1,132.6 | 1,016.9 | |||||||||
| Deferred tax credits | 123.8 | 124.3 | |||||||||
| Asset retirement obligations | 239.3 | 177.7 | |||||||||
| Pension and post-retirement liability | 433.4 | 485.4 | |||||||||
| Regulatory liabilities | 164.6 | 172.0 | |||||||||
| Other Liabilities, Noncurrent | 61.6 | 59.2 | |||||||||
| Liabilities, Noncurrent, Total | 2,155.3 | 2,035.5 | |||||||||
| Common shareholders' equity | |||||||||||
| Common Stock, Value, Issued | 1,563.1 | 1,563.1 | |||||||||
| Retained earnings | 879.6 | 726.8 | |||||||||
| Accumulated other comprehensive loss | (9.6) | (14.9) | |||||||||
| Common Shareholders' Equity, Total | 2,433.1 | 2,275.0 | |||||||||
| Cumulative preferred stock $100 par value | |||||||||||
| Long-term debt | [3] | 2,563.1 | 2,282.8 | ||||||||
| Total Capitalization | $ 4,996.2 | $ 4,557.8 | |||||||||
| Commitments and Contingencies | |||||||||||
| Liabilities and Equity, Total | $ 7,814.6 | $ 7,495.1 | |||||||||
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- Definition Sum of the carrying amounts of deferred costs for nuclear plant refueling outages that are expected to be recognized as a charge against earnings. No definition available.
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- Definition The total of investments and other long-term assets. No definition available.
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- References No definition available.
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- Definition Period end amount of total net PPE in service No definition available.
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| X | ||||||||||
- Definition Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount for accounts payable to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The noncurrent portion of the reserve for accumulated deferred investment tax credits as of the balance sheet date. This is the remaining investment credit, which will reduce the cost of services collected from ratepayers by a ratable portion over the investment's regulatory life. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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| X | ||||||||||
- Definition This element represents the total consolidated (as applicable) capitalization of the entity which is comprised of its long-term debt and equity instruments. The table may be detailed by subsidiary (legal entity) and include information by type of debt or equity detailed by instrument. No definition available.
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| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences, netted by jurisdiction and classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying value of amounts transferred to third parties for security purposes that are expected to be returned or applied towards payment within one year or during the operating cycle, if shorter. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies relating to a source of usable power held for future sale or future use in manufacturing or production process. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of obligation due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The carrying amount as of the balance sheet of nuclear fuel held as property plant and equipment. This amount is net of amortization based on the energy produced over the life of the fuel. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate carrying amount of current liabilities (due within one year or within the normal operating cycle if longer) not separately disclosed in the balance sheet. Includes costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered and of liabilities not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate carrying amount, as of the balance sheet date, of noncurrent obligations not separately disclosed in the balance sheet. Noncurrent liabilities are expected to be paid after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition For a classified balance sheet, the amount recognized in balance sheet as a current liability associated with an underfunded defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement defined benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Period end book value of accumulated depreciation on property, plant and equipment (PPE) that is owned by the regulated operations of the public utility. No definition available.
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| X | ||||||||||
- Definition Period end amount of construction work in progress in public utility. No definition available.
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| X | ||||||||||
- Definition Period end amount of total net PPE. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Period end amount of total gross PPE. No definition available.
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| X | ||||||||||
- Definition The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount at the balance sheet date of borrowings from a bank, not elsewhere enumerated in the taxonomy, with a maturity within one year (or within one operating cycle if longer) from the date of borrowing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Carrying value as of the balance sheet date of obligations incurred and payable for statutory income, sales, use, payroll, excise, real, property and other taxes. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount of financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount of liabilities associated with financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Utility Plant, at Original Cost | ||
| Nuclear fuel, amortization | $ 192.5 | $ 187.5 |
| Common shareholder's equity | ||
| Common stock - shares authorized (in shares) | 250,000,000 | 250,000,000 |
| Common stock-shares issued (in shares) | 154,504,900 | 154,254,037 |
| Treasury stock- shares (in shares) | 101,229 | 91,281 |
| Preferred Stock 3 Point 80 [Member] | ||
| Cumulative preferred stock | ||
| Cumulative preferred stock par value (in dollars per share) | $ 100.00 | $ 100.00 |
| Cumulative preferred stock, Shares issued (in share) | 100,000 | 100,000 |
| Preferred Stock, Dividend Rate, Percentage | 3.80% | 3.80% |
| Preferred Stock 4 Point 50 [Member] | ||
| Cumulative preferred stock | ||
| Cumulative preferred stock par value (in dollars per share) | $ 100.00 | $ 100.00 |
| Cumulative preferred stock, Shares issued (in share) | 100,000 | 100,000 |
| Preferred Stock, Dividend Rate, Percentage | 4.50% | 4.50% |
| Preferred Stock 4 Point 20 [Member] | ||
| Cumulative preferred stock | ||
| Cumulative preferred stock par value (in dollars per share) | $ 100.00 | $ 100.00 |
| Cumulative preferred stock, Shares issued (in share) | 70,000 | 70,000 |
| Preferred Stock, Dividend Rate, Percentage | 4.20% | 4.20% |
| Preferred Stock 4 Point 35 [Member] | ||
| Cumulative preferred stock | ||
| Cumulative preferred stock par value (in dollars per share) | $ 100.00 | $ 100.00 |
| Cumulative preferred stock, Shares issued (in share) | 120,000 | 120,000 |
| Preferred Stock, Dividend Rate, Percentage | 4.35% | 4.35% |
| Kansas City Power and Light Company [Member] | ||
| Utility Plant, at Original Cost | ||
| Nuclear fuel, amortization | $ 192.5 | $ 187.5 |
| Common shareholder's equity | ||
| Common stock - shares authorized (in shares) | 1,000.0 | 1,000.0 |
| Common stock-shares issued (in shares) | 1.0 | 1.0 |
| X | ||||||||||
- Definition Amortization based on the energy produced over the life of the fuel. No definition available.
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The percentage rate used to calculate dividend payments on preferred stock. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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Consolidated Statements of Cash Flows - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Cash Flows from Operating Activities | |||
| Net income (loss) | $ 213.0 | $ 242.8 | $ 250.2 |
| Adjustments to reconcile income to net cash from operating activities: | |||
| Depreciation and amortization | 330.4 | 306.0 | 289.7 |
| Amortization of: | |||
| Nuclear fuel | 26.8 | 26.1 | 22.8 |
| Other | 47.7 | 46.1 | 57.5 |
| Deferred income taxes, net | 124.9 | 125.8 | 134.0 |
| Investment tax credit amortization | (1.4) | (1.4) | (1.7) |
| (Income) loss from equity investments, net of income taxes | (1.2) | 0.0 | 0.2 |
| Other operating activities | 12.9 | (47.2) | 24.1 |
| Net cash from operating activities | 753.1 | 698.2 | 776.8 |
| Cash Flows from Investing Activities | |||
| Utility capital expenditures | (677.1) | (773.7) | (669.0) |
| Allowance for borrowed funds used during construction | (5.8) | (13.0) | (11.8) |
| Purchases of nuclear decommissioning trust investments | (50.9) | (27.5) | (73.5) |
| Proceeds from nuclear decommissioning trust investments | 47.6 | 24.2 | 70.2 |
| Proceeds from sale of transmission assets | 0.0 | 37.7 | 0.0 |
| Other investing activities | (48.2) | (27.5) | (21.7) |
| Net cash from investing activities | (734.4) | (779.8) | (705.8) |
| Cash Flows from Financing Activities | |||
| Issuance of common stock | 3.0 | 4.8 | 4.9 |
| Issuance of long-term debt | 348.8 | 0.0 | 762.5 |
| Proceeds from issuance of long-term debt from remarketing | 146.5 | 0.0 | 0.0 |
| Repayment of long-term debt from remarketing | (146.5) | 0.0 | 0.0 |
| Issuance fees | (3.0) | (0.9) | (9.0) |
| Repayment of long-term debt | (87.0) | (13.4) | (265.3) |
| Net change in short-term borrowings | (128.3) | 245.1 | (424.9) |
| Net change in collateralized short-term borrowings | 4.0 | (4.0) | 1.0 |
| Dividends paid | (155.5) | (145.6) | (137.3) |
| Other financing activities | (2.4) | (2.0) | (1.6) |
| Net cash from financing activities | (20.4) | 84.0 | (69.7) |
| Net Change in Cash and Cash Equivalents | (1.7) | 2.4 | 1.3 |
| Cash and Cash Equivalents at Beginning of Year | 13.0 | 10.6 | 9.3 |
| Cash and Cash Equivalents at End of Year | 11.3 | 13.0 | 10.6 |
| Kansas City Power and Light Company [Member] | |||
| Cash Flows from Operating Activities | |||
| Net income (loss) | 152.8 | 162.4 | 169.0 |
| Adjustments to reconcile income to net cash from operating activities: | |||
| Depreciation and amortization | 235.7 | 213.9 | 198.3 |
| Amortization of: | |||
| Nuclear fuel | 26.8 | 26.1 | 22.8 |
| Other | 29.1 | 29.3 | 34.3 |
| Deferred income taxes, net | 99.4 | 88.4 | 92.1 |
| Investment tax credit amortization | (1.0) | (1.0) | (1.1) |
| Other operating activities | (61.5) | (64.7) | (9.2) |
| Net cash from operating activities | 481.3 | 454.4 | 506.2 |
| Cash Flows from Investing Activities | |||
| Utility capital expenditures | (518.3) | (635.9) | (521.9) |
| Allowance for borrowed funds used during construction | (3.9) | (11.1) | (10.6) |
| Purchases of nuclear decommissioning trust investments | (50.9) | (27.5) | (73.5) |
| Proceeds from nuclear decommissioning trust investments | 47.6 | 24.2 | 70.2 |
| Proceeds from sale of transmission assets | 0.0 | 4.7 | 0.0 |
| Other investing activities | (25.5) | (15.2) | (12.4) |
| Net cash from investing activities | (551.0) | (660.8) | (548.2) |
| Cash Flows from Financing Activities | |||
| Issuance of long-term debt | 348.8 | 0.0 | 412.5 |
| Proceeds from issuance of long-term debt from remarketing | 146.5 | 0.0 | 0.0 |
| Repayment of long-term debt from remarketing | (146.5) | 0.0 | 0.0 |
| Issuance fees | (3.0) | (0.4) | (5.7) |
| Repayment of long-term debt | (85.9) | 0.0 | (2.6) |
| Net change in short-term borrowings | (178.0) | 265.1 | (267.8) |
| Net money pool borrowings | (12.6) | 12.4 | (3.6) |
| Dividends paid | 0.0 | (72.0) | (92.0) |
| Net cash from financing activities | 69.3 | 205.1 | 40.8 |
| Net Change in Cash and Cash Equivalents | (0.4) | (1.3) | (1.2) |
| Cash and Cash Equivalents at Beginning of Year | 2.7 | 4.0 | 5.2 |
| Cash and Cash Equivalents at End of Year | $ 2.3 | $ 2.7 | $ 4.0 |
| X | ||||||||||
- Definition The component of the allowance for funds used during construction during the period based on the interest rate on borrowed funds used in financing the construction of regulated assets. No definition available.
|
| X | ||||||||||
- Definition The noncash expense, not otherwise specified in the taxonomy, charged against earnings in the period to allocate the cost of nuclear fuel over the operating cycle of the nuclear plant. No definition available.
|
| X | ||||||||||
- Definition The amount deducted from an entities' taxes, reflecting a percentage of an amount invested in certain assets spread over the useful life of those assets; the part related to the amortization of investment tax credits. No definition available.
|
| X | ||||||||||
- Definition The net cash inflows or outflows in money pool borrowings. No definition available.
|
| X | ||||||||||
- Definition Proceeds from issuance of long-term debt from remarketing of EIRR Bonds. No definition available.
|
| X | ||||||||||
- Definition Repayment of long-term debt from remarketing of EIRR Bonds No definition available.
|
| X | ||||||||||
- Definition Total increase (decrease) in operating capital plus other cash or noncash adjustments to reconcile net income to cash provided by (used in) operating activities. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization of other deferred costs recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total of the cash outflow during the period which has been paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt and the cost incurred directly for the issuance of equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash outflow or inflow from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow for the purchase of investments that will be held in a decommissioning trust fund. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash inflow from the sale of assets held in a decommissioning trust fund. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash inflow from the additional capital contribution to the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow in other borrowings not otherwise defined in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow for borrowing having initial term of repayment within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
Consolidated Statements of Common Shareholders' Equity - USD ($) $ in Millions |
Total |
Kansas City Power and Light Company [Member] |
Common Stock [Member] |
Common Stock [Member]
Kansas City Power and Light Company [Member]
|
Retained Earnings [Member] |
Retained Earnings [Member]
Kansas City Power and Light Company [Member]
|
Treasury Stock [Member] |
Accumulated Other Comprehensive Income (Loss) [Member] |
Accumulated Other Comprehensive Income (Loss) [Member]
Kansas City Power and Light Company [Member]
|
|---|---|---|---|---|---|---|---|---|---|
| Beginning balance at Dec. 31, 2012 | $ 2,624.7 | $ 1,563.1 | $ 758.8 | $ 559.4 | $ (5.1) | $ (38.4) | $ (25.8) | ||
| Beginning balance (in shares) at Dec. 31, 2012 | 153,779,806 | 1 | |||||||
| Beginning balance, treasury stock (in shares) at Dec. 31, 2012 | (250,236) | ||||||||
| Issuance of common stock | $ 4.9 | ||||||||
| Issuance of common stock (in shares) | 215,815 | ||||||||
| Equity compensation expense, net of forfeitures | $ 0.4 | ||||||||
| Unearned Compensation [Abstract] | |||||||||
| Issuance of restricted common stock | (1.8) | ||||||||
| Forfeiture of restricted common stock | 0.1 | ||||||||
| Compensation expense recognized | 2.1 | ||||||||
| Stockholders' Equity, Other | 0.7 | ||||||||
| Net income (loss) | $ 250.2 | $ 169.0 | 250.2 | 169.0 | |||||
| Dividends: | |||||||||
| Common stock | (135.7) | (92.0) | |||||||
| Preferred stock - at required rates | (1.6) | ||||||||
| Performance shares | (0.3) | ||||||||
| Treasury shares acquired | $ (1.6) | ||||||||
| Treasury shares acquired (in shares) | (73,201) | ||||||||
| Treasury shares reissued | $ 3.9 | ||||||||
| Treasury shares reissued (in shares) | 194,147 | ||||||||
| Derivative hedging activity, net of tax | 11.6 | 5.6 | 11.6 | 5.6 | |||||
| Change in unrecognized pension expense, net of tax | 1.5 | 1.5 | |||||||
| Ending balance at Dec. 31, 2013 | 3,474.4 | 2,179.3 | $ 2,631.1 | $ 1,563.1 | 871.4 | 636.4 | $ (2.8) | (25.3) | (20.2) |
| Ending balance, treasury stock (in shares) at Dec. 31, 2013 | (129,290) | ||||||||
| Ending balance (in shares) at Dec. 31, 2013 | 153,995,621 | 1 | |||||||
| Issuance of common stock | $ 6.7 | ||||||||
| Issuance of common stock (in shares) | 258,416 | ||||||||
| Equity compensation expense, net of forfeitures | $ 0.5 | ||||||||
| Unearned Compensation [Abstract] | |||||||||
| Issuance of restricted common stock | (2.1) | ||||||||
| Forfeiture of restricted common stock | 0.0 | ||||||||
| Compensation expense recognized | 2.0 | ||||||||
| Stockholders' Equity, Other | 1.1 | ||||||||
| Net income (loss) | 242.8 | 162.4 | 242.8 | 162.4 | |||||
| Dividends: | |||||||||
| Common stock | (144.0) | (72.0) | |||||||
| Preferred stock - at required rates | (1.6) | ||||||||
| Performance shares | (0.8) | ||||||||
| Treasury shares acquired | $ (2.2) | ||||||||
| Treasury shares acquired (in shares) | (85,744) | ||||||||
| Treasury shares reissued | $ 2.7 | ||||||||
| Treasury shares reissued (in shares) | 123,753 | ||||||||
| Derivative hedging activity, net of tax | 8.0 | 5.3 | 8.0 | 5.3 | |||||
| Change in unrecognized pension expense, net of tax | (1.4) | (1.4) | |||||||
| Ending balance at Dec. 31, 2014 | $ 3,586.1 | 2,275.0 | $ 2,639.3 | $ 1,563.1 | 967.8 | 726.8 | $ (2.3) | (18.7) | (14.9) |
| Ending balance, treasury stock (in shares) at Dec. 31, 2014 | (91,281) | (91,281) | |||||||
| Ending balance (in shares) at Dec. 31, 2014 | 154,254,037 | 1 | |||||||
| Issuance of common stock | $ 6.6 | ||||||||
| Issuance of common stock (in shares) | 250,863 | ||||||||
| Equity compensation expense, net of forfeitures | $ 1.9 | ||||||||
| Unearned Compensation [Abstract] | |||||||||
| Issuance of restricted common stock | (2.4) | ||||||||
| Forfeiture of restricted common stock | 0.5 | ||||||||
| Compensation expense recognized | 1.8 | ||||||||
| Stockholders' Equity, Other | (1.0) | ||||||||
| Net income (loss) | $ 213.0 | 152.8 | 213.0 | 152.8 | |||||
| Dividends: | |||||||||
| Common stock | (153.9) | 0.0 | |||||||
| Preferred stock - at required rates | (1.6) | ||||||||
| Performance shares | (0.9) | ||||||||
| Treasury shares acquired | $ (2.0) | ||||||||
| Treasury shares acquired (in shares) | (76,468) | ||||||||
| Treasury shares reissued | $ 1.7 | ||||||||
| Treasury shares reissued (in shares) | 66,520 | ||||||||
| Derivative hedging activity, net of tax | 5.7 | 5.3 | 5.7 | 5.3 | |||||
| Change in unrecognized pension expense, net of tax | 1.0 | 1.0 | |||||||
| Ending balance at Dec. 31, 2015 | $ 3,656.5 | $ 2,433.1 | $ 2,646.7 | $ 1,563.1 | $ 1,024.4 | $ 879.6 | $ (2.6) | $ (12.0) | $ (9.6) |
| Ending balance, treasury stock (in shares) at Dec. 31, 2015 | (101,229) | (101,229) | |||||||
| Ending balance (in shares) at Dec. 31, 2015 | 154,504,900 | 1 |
| X | ||||||||||
- Definition Amount recorded to Additional Paid in Capital to reduce unearned compensation related to the forfeiture of restricted common stock. No definition available.
|
| X | ||||||||||
- Definition Amount recorded to Additional Paid in Capital to represent unearned compensation related to the issuance of restricted common stock. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of equity-based compensation, related to restricted stock units or restricted stock awards, recognized as expense or an asset, if compensation is capitalized. No definition available.
|
| X | ||||||||||
- Definition This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation". Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of paid and unpaid common stock dividends declared with the form of settlement in cash. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of paid and unpaid cash dividends declared and applicable to holders of share-based compensation, for example, but not limited to, non-vested shares, stock options, or restricted stock units. No definition available.
|
| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of new stock issued during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of treasury shares (units) reissued during the period, excluding reissuance of shares (units) held in treasury used to satisfy equity-based compensation obligations exercised by the holders of such rights. Upon reissuance of shares (units) from treasury, either the common or preferred stock (unit) reissued is outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Equity impact of the value of treasury stock (units) reissued during the period, excluding reissuance of shares (units) held in treasury used to satisfy equity-based compensation obligations exercised by the holders of such rights. Upon reissuance of shares (units) from treasury, either the common or preferred stock (unit) reissued is outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This element represents movements included in the statement of changes in stockholders' equity which are not separately disclosed or provided for elsewhere in the taxonomy. No definition available.
|
| X | ||||||||||
- Definition Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of shares that have been repurchased during the period and are being held in treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Consolidated Statements of Common Shareholders' Equity (Parenthetical) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Stock Transactions, Parenthetical Disclosures [Abstract] | |||
| Common Stock, Dividends, Per Share, Declared | $ 0.9975 | $ 0.935 | $ 0.8825 |
| X | ||||||||||
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
Summary of Significant Accounting Policies |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accounting Policies [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Significant Accounting Policies [Text Block] | 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization Great Plains Energy, a Missouri corporation incorporated in 2001, is a public utility holding company and does not own or operate any significant assets other than the stock of its subsidiaries. Great Plains Energy's wholly owned direct subsidiaries with significant operations are as follows:
Great Plains Energy also wholly owns GPE Transmission Holding Company, LLC (GPETHC). GPETHC owns 13.5% of Transource Energy, LLC (Transource) with the remaining 86.5% owned by AEP Transmission Holding Company, LLC (AEPTHC), a subsidiary of American Electric Power Company, Inc. GPETHC accounts for its investment in Transource under the equity method. Transource is focused on the development of competitive electric transmission projects. Each of Great Plains Energy's and KCP&L's consolidated financial statements includes the accounts of their subsidiaries. Intercompany transactions have been eliminated. Great Plains Energy's sole reportable business segment is electric utility. See Note 22 for additional information. Use of Estimates The process of preparing financial statements in conformity with Generally Accepted Accounting Principles (GAAP) requires the use of estimates and assumptions that affect the reported amounts of certain types of assets, liabilities, revenues and expenses. Such estimates primarily relate to unsettled transactions and events as of the date of the financial statements. Accordingly, upon settlement, actual results may differ from estimated amounts. Cash and Cash Equivalents Cash equivalents consist of highly liquid investments with original maturities of three months or less at acquisition. Funds on Deposit Funds on deposit consist primarily of cash provided to counterparties in support of margin requirements related to commodity purchases, commodity swaps and futures contracts. Pursuant to individual contract terms with counterparties, deposit amounts required vary with changes in market prices, credit provisions and various other factors. Interest is earned on most funds on deposit. Great Plains Energy also holds funds on deposit from counterparties in the same manner. These funds are included in other current liabilities on the consolidated balance sheets. Fair Value of Financial Instruments The following methods and assumptions were used to estimate the fair value of each class of financial instrument for which it is practicable to estimate that value. Nuclear decommissioning trust fund - KCP&L's nuclear decommissioning trust fund assets are recorded at fair value based on quoted market prices of the investments held by the fund and/or valuation models. Derivative instruments - The fair value of derivative instruments is estimated using market quotes, over-the-counter forward price and volatility curves and correlation among fuel prices, net of estimated credit risk. Pension plans - For financial reporting purposes, the market value of plan assets is the fair value. For regulatory reporting purposes, a five-year smoothing of assets is used to determine fair value. Derivative Instruments The Company records derivative instruments on the balance sheet at fair value in accordance with GAAP. Great Plains Energy and KCP&L enter into derivative contracts to manage exposure to commodity price and interest rate fluctuations. Derivative instruments are used solely for hedging purposes and are not issued or held for speculative reasons. The Company considers various qualitative factors, such as contract and market place attributes, in designating derivative instruments at inception. Great Plains Energy and KCP&L may elect the normal purchases and normal sales (NPNS) exception, which requires the effects of the derivative to be recorded when the underlying contract settles. Great Plains Energy and KCP&L account for derivative instruments that are not designated as NPNS as non-hedging derivatives, which are recorded as assets or liabilities on the consolidated balance sheets at fair value. See Note 18 for additional information regarding derivative financial instruments and hedging activities. Great Plains Energy and KCP&L offset fair value amounts recognized for derivative instruments under master netting arrangements, which include rights to reclaim cash collateral (a receivable), or the obligation to return cash collateral (a payable). Utility Plant Great Plains Energy's and KCP&L's utility plant is stated at historical cost. These costs include taxes, an allowance for the cost of borrowed and equity funds used to finance construction and payroll-related costs, including pensions and other fringe benefits. Replacements, improvements and additions to units of property are capitalized. Repairs of property and replacements of items not considered to be units of property are expensed as incurred (except as discussed under Deferred Refueling Outage Costs). When property units are retired or otherwise disposed, the original cost, net of salvage, is charged to accumulated depreciation. Substantially all of KCP&L's utility plant is pledged as collateral for KCP&L's mortgage bonds under the General Mortgage Indenture and Deed of Trust dated December 1, 1986, as supplemented. Substantially all of GMO's St. Joseph Light & Power division utility plant is pledged as collateral for GMO's mortgage bonds under the General Mortgage Indenture and Deed of Trust dated April 1, 1946, as supplemented. As prescribed by The Federal Energy Regulatory Commission (FERC), Allowance for Funds Used During Construction (AFUDC) is charged to the cost of the plant during construction. AFUDC equity funds are included as a non-cash item in non-operating income and AFUDC borrowed funds are a reduction of interest charges. The rates used to compute gross AFUDC are compounded semi-annually. The rates used to compute gross AFUDC for KCP&L averaged 3.0% in 2015, 5.7% in 2014 and 6.1% in 2013. The rates used to compute gross AFUDC for GMO averaged 4.2% in 2015, 6.1% in 2014 and 2.1% in 2013. Great Plains Energy's and KCP&L's balances of utility plant, at original cost, with a range of estimated useful lives are listed in the following tables.
(a) Includes $136.5 million and $72.4 million at December 31, 2015 and 2014, respectively, of land and other assets that are not depreciated. Depreciation and Amortization Depreciation and amortization of utility plant other than nuclear fuel is computed using the straight-line method over the estimated lives of depreciable property based on rates approved by state regulatory authorities. Annual depreciation rates average approximately 3%. Nuclear fuel is amortized to fuel expense based on the quantity of heat produced during the generation of electricity. Great Plains Energy's depreciation expense was $299.4 million, $277.9 million and $265.4 million for 2015, 2014 and 2013, respectively. KCP&L's depreciation expense was $208.5 million, $189.7 million and $179.2 million for 2015, 2014 and 2013, respectively. Nuclear Plant Decommissioning Costs Nuclear plant decommissioning cost estimates are based on the immediate dismantlement method and include the costs of decontamination, dismantlement and site restoration. Based on these cost estimates, KCP&L contributes to a tax-qualified trust fund to be used to decommission Wolf Creek Generating Station (Wolf Creek). Related liabilities for decommissioning are included on Great Plains Energy's and KCP&L's balance sheets in Asset Retirement Obligations (AROs). As a result of the authorized regulatory treatment and related regulatory accounting, differences between the decommissioning trust fund asset and the related ARO are recorded as a regulatory asset or liability. See Note 7 for discussion of AROs including those associated with nuclear plant decommissioning costs. Deferred Refueling Outage Costs KCP&L uses the deferral method to account for operations and maintenance expenses incurred in support of Wolf Creek's scheduled refueling outages and amortizes them evenly (monthly) over the unit's operating cycle, which is approximately 18 months, until the next scheduled outage. Replacement power costs during an outage are expensed as incurred. Regulatory Matters KCP&L and GMO defer items on the balance sheet resulting from the effects of the ratemaking process, which would not be recorded if KCP&L and GMO were not regulated. See Note 5 for additional information concerning regulatory matters. Revenue Recognition Great Plains Energy and KCP&L recognize revenues on sales of electricity when the service is provided. Revenues recorded include electric services provided but not yet billed by KCP&L and GMO. Unbilled revenues are recorded for kWh usage in the period following the customers' billing cycle to the end of the month. KCP&L's and GMO's estimate is based on net system kWh usage less actual billed kWhs. KCP&L's and GMO's estimated unbilled kWhs are allocated and priced by regulatory jurisdiction across the rate classes based on actual billing rates. KCP&L and GMO collect from customers gross receipts taxes levied by state and local governments. These taxes from KCP&L's Missouri customers are recorded gross in operating revenues and general taxes on Great Plains Energy's and KCP&L's statements of comprehensive income. KCP&L's gross receipts taxes collected from Missouri customers were $62.0 million, $60.4 million and $58.9 million in 2015, 2014 and 2013, respectively. These taxes from KCP&L's Kansas customers and GMO's customers are recorded net in operating revenues on Great Plains Energy's and KCP&L's statements of comprehensive income. Great Plains Energy and KCP&L collect sales taxes from customers and remit to state and local governments. These taxes are presented on a net basis on Great Plains Energy's and KCP&L's statements of comprehensive income. Great Plains Energy and KCP&L record sale and purchase activity on a net basis in wholesale revenue or purchased power when transacting with Regional Transmission Organization (RTO)/Independent System Operator (ISO) markets. Allowance for Doubtful Accounts This reserve represents estimated uncollectible accounts receivable and is based on management's judgment considering historical loss experience and the characteristics of existing accounts. Provisions for losses on receivables are expensed to maintain the allowance at a level considered adequate to cover expected losses. Receivables are charged off against the reserve when they are deemed uncollectible. Property Gains and Losses Net gains and losses from the sale of assets and businesses and from asset impairments are recorded in operating expenses. Asset Impairments Long-lived assets and finite-lived intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the undiscounted expected future cash flows from an asset to be held and used is less than the carrying value of the asset, an asset impairment must be recognized in the financial statements. The amount of impairment recognized is the excess of the carrying value of the asset over its fair value. Goodwill and indefinite lived intangible assets are tested for impairment annually and when an event occurs indicating the possibility that an impairment exists. The annual test must be performed at the same time each year. If the fair value of a reporting unit is less than its carrying value including goodwill, an impairment charge for goodwill must be recognized in the financial statements. To measure the amount of the impairment loss to recognize, the implied fair value of the reporting unit goodwill is compared with its carrying value. Income Taxes Income taxes are accounted for using the asset/liability approach. Deferred tax assets and liabilities are determined based on the temporary differences between the financial reporting and tax bases of assets and liabilities, applying enacted statutory tax rates in effect for the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion of the deferred tax assets will not be realized. Great Plains Energy and KCP&L recognize tax benefits based on a “more-likely-than-not” recognition threshold. In addition, Great Plains Energy and KCP&L recognize interest accrued related to unrecognized tax benefits in interest expense and penalties in non-operating expenses. Great Plains Energy files a consolidated federal income tax return as well as unitary and combined income tax returns in several state jurisdictions with Kansas and Missouri being the most significant. Income taxes for consolidated or combined subsidiaries are allocated to the subsidiaries based on separate company computations of income or loss. KCP&L's income tax provision includes taxes allocated based on its separate company income or loss. Great Plains Energy and KCP&L have established a net regulatory asset for the additional future revenues to be collected from customers for deferred income taxes. Tax credits are recognized in the year generated except for certain KCP&L and GMO investment tax credits that have been deferred and amortized over the remaining service lives of the related properties. Environmental Matters Environmental costs are accrued when it is probable a liability has been incurred and the amount of the liability can be reasonably estimated. Basic and Diluted Earnings per Common Share Calculation To determine basic earnings per common share (EPS), preferred stock dividend requirements are deducted from net income before dividing by the average number of common shares outstanding. The effect of dilutive securities, calculated using the treasury stock method, assumes the issuance of common shares applicable to performance shares and restricted stock. The following table reconciles Great Plains Energy's basic and diluted EPS.
Anti-dilutive shares excluded from the computation of diluted EPS are detailed in the following table.
Dividends Declared In February 2016, Great Plains Energy's Board of Directors (Board) declared a quarterly dividend of $0.2625 per share on Great Plains Energy's common stock. The common dividend is payable March 21, 2016, to shareholders of record as of February 29, 2016. The Board also declared regular dividends on Great Plains Energy's preferred stock, payable June 1, 2016, to shareholders of record as of May 10, 2016. New Accounting Standards ASU No. 2015-03 - Simplifying the Presentation of Debt Issuance Costs In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-03, Simplifying the Presentation of Debt Issuance Costs, which requires that debt issuance costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The new guidance is to be applied retrospectively and is effective for interim and annual periods beginning after December 15, 2015, with early adoption permitted. The Companies elected to early adopt at December 31, 2015, and accordingly have retrospectively adjusted prior periods. The following table reflects the change on the line items of Great Plains Energy's and KCP&L's consolidated balance sheets at December 31, 2014.
ASU No. 2015-07 - Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) In May 2015, the FASB issued ASU No. 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). This guidance removes the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. The new guidance is effective for interim and annual periods beginning after December 15, 2015, with early adoption permitted. The Companies elected to early adopt at December 31, 2015, and accordingly have retrospectively adjusted prior periods. ASU No. 2015-17 - Balance Sheet Classification of Deferred Taxes In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes, which simplifies the presentation of deferred taxes by requiring deferred tax assets and liabilities be classified as noncurrent on the balance sheet. The new guidance is effective for interim and annual periods beginning after December 15, 2016, with early adoption permitted. The Companies elected to early adopt this guidance, prospectively, at December 31, 2015. Prior periods were not retrospectively adjusted. ASU No. 2014-09 - Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in GAAP when it becomes effective. In August 2015, the FASB issued ASU No. 2015-14, deferring the effective date of ASU No. 2014-09 one year, from January 1, 2017, to January 1, 2018. The Companies plan to adopt ASU No. 2014-09 on January 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition method. The Companies are evaluating the effect that ASU No. 2014-09 will have on their consolidated financial statements and related disclosures and have not yet selected a transition method nor have they determined the effect of the standard on their ongoing financial reporting. |
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- Definition The entire disclosure for the organization, consolidation and basis of presentation of financial statements disclosure, and significant accounting policies of the reporting entity. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Supplemental Cash Flow Information |
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| Supplemental Cash Flow Elements [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cash Flow, Supplemental Disclosures [Text Block] | 2. SUPPLEMENTAL CASH FLOW INFORMATION
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- Definition The entire disclosure for supplemental cash flow activities, including cash, noncash, and part noncash transactions, for the period. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Receivables |
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| Loans Notes Trade And Other Receivables Disclosure And Transfers And Servicing Of Financial Asset [Text Block] | 3. RECEIVABLES Great Plains Energy's and KCP&L's receivables are detailed in the following table.
Great Plains Energy's and KCP&L's other receivables at December 31, 2015, and 2014, consisted primarily of receivables from partners in jointly owned electric utility plants and wholesale sales receivables. Sale of Accounts Receivable – KCP&L and GMO KCP&L and GMO sell all of their retail electric accounts receivable to their wholly owned subsidiaries, KCP&L Receivables Company and GMO Receivables Company, respectively, which in turn sell an undivided percentage ownership interest in the accounts receivable to Victory Receivables Corporation, an independent outside investor. Each of KCP&L Receivables Company's and GMO Receivables Company's sale of the undivided percentage ownership interest in accounts receivable to Victory Receivables Corporation is accounted for as a secured borrowing with accounts receivable pledged as collateral and a corresponding short-term collateralized note payable recognized on the balance sheets. At December 31, 2015, and 2014, Great Plains Energy's accounts receivable pledged as collateral and the corresponding short-term collateralized note payable were $175.0 million and $171.0 million, respectively. At December 31, 2015, and 2014, KCP&L's accounts receivable pledged as collateral and the corresponding short-term collateralized note payable were $110.0 million. KCP&L's agreement expires in September 2016 and allows for $110 million in aggregate outstanding principal amount at any time. GMO's agreement expires in September 2016 and allows for $65 million in aggregate outstanding principal from mid-November through mid-June and then increases to $80 million from mid-June through mid-November. |
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- Definition Includes disclosure of claims held for amounts due a company. Examples include trade accounts receivables, notes receivables, loans receivables. Also provides the disclosures pertaining to a transferor's continuing involvement in financial assets that it has transferred in a securitization or asset-backed financing arrangements. No definition available.
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Nuclear Plant |
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| Nuclear Plant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Nuclear Plant | 4. NUCLEAR PLANT KCP&L owns 47% of Wolf Creek, its only nuclear generating unit. Wolf Creek is located in Coffey County, Kansas, just northeast of Burlington, Kansas. Wolf Creek's operating license expires in 2045. Wolf Creek is regulated by the Nuclear Regulatory Commission (NRC), with respect to licensing, operations and safety-related requirements. Spent Nuclear Fuel and High-Level Radioactive Waste Under the Nuclear Waste Policy Act of 1982, the Department of Energy (DOE) is responsible for the permanent disposal of spent nuclear fuel. Wolf Creek paid the DOE a quarterly fee of one-tenth of a cent for each kWh of net nuclear generation delivered and sold for the future disposal of spent nuclear fuel. In May 2014, this fee was set to zero. In 2010, the DOE filed a motion with the NRC to withdraw its then pending application to the NRC to construct a national repository for the disposal of spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. An NRC board denied the DOE's motion to withdraw its application. In 2011, the NRC reexamined its decision and ordered the licensing board, consistent with budgetary limitations, to close out its work on the DOE's application. In August 2013, a federal court of appeals ruled that the NRC must resume its review of the DOE's application. Wolf Creek is currently evaluating alternatives for expanding its existing on-site spent nuclear fuel storage to provide additional capacity prior to 2025. Management cannot predict when, or if, an off-site storage site or alternative disposal site will be available to receive Wolf Creek's spent nuclear fuel and will continue to monitor this activity. Low-Level Radioactive Waste Wolf Creek disposes of most of its low-level radioactive waste (Class A waste) at an existing third-party repository in Utah. Management expects that the site located in Utah will remain available to Wolf Creek for disposal of its Class A waste. Wolf Creek has contracted with a waste processor that will process, take title and dispose in another state most of the remainder of Wolf Creek's low-level radioactive waste (Classes B and C waste, which is higher in radioactivity but much lower in volume). Should on-site waste storage be needed in the future, Wolf Creek has current storage capacity on site for about four years' generation of Classes B and C waste and believes it will be able to expand that storage capacity as needed if it becomes necessary to do so. Nuclear Plant Decommissioning Costs The Public Service Commission of the State of Missouri (MPSC) and The State Corporation Commission of the State of Kansas (KCC) require KCP&L and the other owners of Wolf Creek to submit an updated decommissioning cost study every three years and to propose funding levels. The most recent study was submitted to the MPSC and KCC in August 2014 and is the basis for the current cost of decommissioning estimates in the following table. Funding levels included in KCP&L retail rates have not changed.
(a) Total future cost over an eight year decommissioning period (b) The 6.43% and 5.89% rate of return for KCC and MPSC, respectively, is through 2025. The rates then systematically decrease through 2053 to 0.72% and 2.22% for KCC and MPSC, respectively, based on the assumption that the fund's investment mix will become increasingly conservative as the decommissioning period approaches. Nuclear Decommissioning Trust Fund In 2015 and 2014, KCP&L contributed approximately $3.3 million to a tax-qualified trust fund to be used to decommission Wolf Creek. Amounts funded are charged to other operating expense and recovered in customers' rates. The funding level assumes a projected level of return on trust assets. If the actual return on trust assets is below the projected level or actual decommissioning costs are higher than estimated, KCP&L could be responsible for the balance of funds required; however, while there can be no assurances, management believes a rate increase would be allowed to recover decommissioning costs over the remaining life of the unit. The following table summarizes the change in Great Plains Energy's and KCP&L's nuclear decommissioning trust fund.
The nuclear decommissioning trust is reported at fair value on the balance sheets and is invested in assets as detailed in the following table.
The weighted average maturity of debt securities held by the trust at December 31, 2015, was approximately 8 years. The costs of securities sold are determined on the basis of specific identification. The following table summarizes the realized gains and losses from the sale of securities in the nuclear decommissioning trust fund.
Nuclear Insurance The owners of Wolf Creek (Owners) maintain nuclear insurance for Wolf Creek for nuclear liability, nuclear property and accidental outage. These policies contain certain industry standard exclusions, including, but not limited to, ordinary wear and tear, and war. The nuclear property insurance programs subscribed to by members of the nuclear power generating industry include industry aggregate limits for acts of terrorism and related losses, including replacement power costs. There is no industry aggregate limit for liability claims related to terrorism, regardless of the number of acts of terrorism affecting Wolf Creek or any other nuclear energy liability policy or the number of policies in place. An industry aggregate limit of $3.2 billion plus any reinsurance recoverable by Nuclear Electric Insurance Limited (NEIL), the Owners' insurance provider, exists for property claims related to nuclear acts of terrorism, including accidental outage power costs for nuclear acts of terrorism affecting Wolf Creek or any other nuclear energy facility property policy within twelve months from the date of the first act. An industry aggregate limit of $1.8 billion exists for property claims related to non-nuclear acts of terrorism. These limits plus any recoverable reinsurance are the maximum amount to be paid to members who sustain losses or damages from these types of terrorist acts. In addition, industry-wide retrospective assessment programs (discussed below) can apply once these insurance programs have been exhausted. In the event of a catastrophic loss at Wolf Creek, the insurance coverage may not be adequate to cover property damage and extra expenses incurred. Uninsured losses, to the extent not recovered through rates, would be assumed by KCP&L and the other owners and could have a material effect on Great Plains Energy's and KCP&L's results of operations, financial position and cash flows. Nuclear Liability Insurance Pursuant to the Price-Anderson Act, which was reauthorized through December 31, 2025, by the Energy Policy Act of 2005, the Owners are required to insure against public liability claims resulting from nuclear incidents to the full limit of public liability, which is currently $13.5 billion. This limit of liability consists of the maximum available commercial insurance of $0.4 billion and the remaining $13.1 billion is provided through an industry-wide retrospective assessment program mandated by law, known as the Secondary Financial Protection (SFP) program. Under the SFP program, the Owners can be assessed up to $127.3 million ($59.8 million, KCP&L's 47% share) per incident at any commercial reactor in the country, payable at no more than $19.0 million ($8.9 million, KCP&L's 47% share) per incident per year. This assessment is subject to an inflation adjustment based on the Consumer Price Index and applicable premium taxes. In addition, the U.S. Congress could impose additional revenue-raising measures to pay claims. Nuclear Property Insurance The Owners carry decontamination liability, premature decommissioning liability and property damage insurance from NEIL for Wolf Creek totaling approximately $2.8 billion ($1.3 billion, KCP&L's 47% share). In the event of an accident, insurance proceeds must first be used for reactor stabilization and site decontamination in accordance with a plan mandated by the NRC. KCP&L's share of any remaining proceeds can be used for further decontamination, property damage restoration and premature decommissioning costs. Premature decommissioning coverage applies only if an accident at Wolf Creek exceeds $500 million in property damage and decontamination expenses, and only after trust funds have been exhausted. Accidental Nuclear Outage Insurance The Owners also carry additional insurance from NEIL to cover costs of replacement power and other extra expenses incurred in the event of a prolonged outage resulting from accidental property damage at Wolf Creek. Under all NEIL policies, the Owners are subject to retrospective assessments if NEIL losses, for each policy year, exceed the accumulated funds available to the insurer under that policy. The estimated maximum amount of retrospective assessments under the current policies could total approximately $42.2 million ($22.4 million, KCP&L's 47% share) per policy year. |
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- References No definition available.
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- Definition This element can be used to encapsulate the entire disclosure for plant used in connection with the generation of nuclear energy. No definition available.
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Regulatory Matters |
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| Regulated Operations [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Regulatory Matters | 5. REGULATORY MATTERS KCP&L Kansas Rate Case Proceedings In January 2015, KCP&L filed an application with KCC to request an increase to its retail revenues of $67.3 million, with a return on equity of 10.3% and a rate-making equity ratio of 50.48%. The request included costs to install environmental upgrades at the La Cygne Station, upgrades at Wolf Creek and other infrastructure and system improvements made to be able to provide reliable electric service. In September 2015, KCC issued an order for KCP&L authorizing an increase in annual revenues of $48.7 million, a return on equity of 9.3% and a rate-making equity ratio of 50.48%. The rates established by the order took effect on October 1, 2015, and are effective unless and until modified by KCC or stayed by a court. KCP&L filed a Petition for Judicial Review with the Court of Appeals of Kansas in November 2015 regarding various issues. KCP&L Missouri Rate Case Proceedings In October 2014, KCP&L filed an application with the MPSC to request an increase to its retail revenues of $120.9 million (subsequently adjusted to $112.7 million), with a return on equity of 10.3% and a rate-making equity ratio of 50.36%. The request included recovery of increased transmission and property tax expenses, costs to install environmental upgrades at the La Cygne Station, upgrades at Wolf Creek and other infrastructure and system improvements made to be able to provide reliable electric service. KCP&L also requested authorization to implement a Fuel Adjustment Clause (FAC). In September 2015, the MPSC issued an order for KCP&L authorizing an increase in annual revenues of $89.7 million, a return on equity of 9.5% and a rate-making equity ratio of approximately 50.09%. The MPSC also approved KCP&L’s request to implement a FAC. The rates established by the order took effect on September 29, 2015, and are effective unless and until modified by the MPSC or stayed by a court. Notices of Appeal of the September 2015 MPSC order were filed with the Missouri Court of Appeals, Western District, by KCP&L in October 2015 and by The Office of the Public Counsel and Midwest Energy Consumers' Group in November 2015 regarding various issues. GMO Missouri Rate Case Proceedings In February 2016, GMO filed an application with the MPSC to request an increase to its retail revenues of $59.3 million, with a return on equity of 9.9% and a rate-making equity ratio of 54.83%. The request included recovery of increased transmission and property tax expenses as well as costs for infrastructure and system improvements made to be able to provide reliable electric service. Regulatory Assets and Liabilities Great Plains Energy and KCP&L have recorded assets and liabilities on their consolidated balance sheets resulting from the effects of the ratemaking process, which would not otherwise be recorded if the Companies were not regulated. Regulatory assets represent incurred costs that are probable of recovery from future revenues. Regulatory liabilities represent future reductions in revenues or refunds to customers. Management regularly assesses whether regulatory assets and liabilities are probable of future recovery or refund by considering factors such as decisions by the MPSC, KCC or FERC in KCP&L's and GMO's rate case filings; decisions in other regulatory proceedings, including decisions related to other companies that establish precedent on matters applicable to the Companies; and changes in laws and regulations. If recovery or refund of regulatory assets or liabilities is not approved by regulators or is no longer deemed probable, these regulatory assets or liabilities are recognized in the current period results of operations. The Companies' continued ability to meet the criteria for recording regulatory assets and liabilities may be affected in the future by restructuring and deregulation in the electric industry or changes in accounting rules. In the event that the criteria no longer applied to any or all of the Companies' operations, the related regulatory assets and liabilities would be written off unless an appropriate regulatory recovery mechanism were provided. Additionally, these factors could result in an impairment on utility plant assets. Great Plains Energy's and KCP&L's regulatory assets and liabilities are detailed in the following table.
(a) Amortized over the life of the related new debt issuances or the remaining lives of the old debt issuances if no new debt was issued. (b) Represents unrecognized gains and losses, prior service and transition costs that will be recognized in future net periodic pension and post-retirement costs, pension settlements amortized over various periods and financial and regulatory accounting method differences that will be eliminated over the life of the pension plans. Of these amounts, $343.7 million and $54.5 million for KCP&L and GMO, respectively, are not included in rate base and are amortized over various periods. (c) $8.3 million not included in rate base and amortized over various periods. (d) $7.4 million not included in rate base and amortized over various periods. (e) Not included in rate base and amortized over various periods. (f) Represents fair value of derivative instruments for commodity contracts. Settlements of the contracts are recognized in the income statement and included in fuel recovery mechanisms. (g) Included in rate base and amortized through 2038. (h) Included in rate base and amortized through 2058. (i) Included in rate base and amortized through 2040. (j) Estimated cumulative net provision for future removal costs. |
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- Definition The entire disclosure for public utilities. No definition available.
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- References No definition available.
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Goodwill and Intangible Assets |
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| Goodwill and Intangible Assets Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Goodwill and Intangible Assets [Text Block] | 6. GOODWILL AND INTANGIBLE ASSETS Accounting rules require goodwill to be tested for impairment annually and when an event occurs indicating the possibility that an impairment exists. The annual impairment test for the $169.0 million of GMO acquisition goodwill was conducted on September 1, 2015. The goodwill impairment test is a two step process. The first step compares the fair value of a reporting unit to its carrying amount, including goodwill, to identify potential impairment. If the carrying amount exceeds the fair value of the reporting unit, the second step of the test is performed, consisting of assignment of the reporting unit's fair value to its assets and liabilities to determine an implied fair value of goodwill, which is compared to the carrying amount of goodwill to determine the impairment loss, if any, to be recognized in the financial statements. Great Plains Energy's regulated electric utility operations are considered one reporting unit for assessment of impairment, as they are included within the same operating segment and have similar economic characteristics. The determination of fair value of the reporting unit consisted of two valuation techniques: an income approach consisting of a discounted cash flow analysis and a market approach consisting of a determination of reporting unit invested capital using market multiples derived from the historical revenue, earnings before interest, income taxes, depreciation and amortization (EBITDA), net utility asset values and market prices of stock of peer companies. The results of the two techniques were evaluated and weighted to determine a point within the range that management considered representative of fair value for the reporting unit. Fair value of the reporting unit exceeded the carrying amount, including goodwill; therefore, there was no impairment of goodwill. Great Plains Energy's and KCP&L's intangible assets are included in electric utility plant on the consolidated balance sheets and are detailed in the following table.
Great Plains Energy's and KCP&L's amortization expense related to intangible assets is detailed in the following table.
The following table provides the estimated amortization expense related to Great Plains Energy's and KCP&L's intangible assets for 2016 through 2020 for the intangible assets included in the consolidated balance sheets at December 31, 2015.
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- References No definition available.
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- Definition The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Asset Retirement Obligations |
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| Asset Retirement Obligation Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Asset Retirement Obligations [Text Block] | 7. ASSET RETIREMENT OBLIGATIONS AROs associated with tangible long-lived assets are legal obligations that exist under enacted laws, statutes and written or oral contracts, including obligations arising under the doctrine of promissory estoppel. These liabilities are recognized at estimated fair value as incurred with a corresponding amount capitalized as part of the cost of the related long-lived assets and depreciated over their useful lives. Accretion of the liabilities due to the passage of time is recorded to a regulatory asset and/or liability. Changes in the estimated fair values of the liabilities are recognized when known. KCP&L has AROs related to decommissioning Wolf Creek, site remediation of its Spearville Wind Energy Facilities, asbestos abatement, removal of storage tanks and closure and post-closure of ponds and landfills containing coal combustion residuals (CCRs). GMO has AROs related to asbestos abatement, removal of storage tanks and closure and post-closure of ponds and landfills containing CCRs. Additionally, certain wiring used in Great Plains Energy's and KCP&L's generating stations include asbestos insulation, which would require special handling if disturbed. Due to the inability to reasonably estimate the quantities or the amount of disturbance that will be necessary during dismantlement at the end of the life of a plant, the fair value of this ARO cannot be reasonably estimated at this time. Management will continue to monitor the obligation and will recognize a liability in the period in which sufficient information becomes available to reasonably estimate its fair value. On April 17, 2015, the Environmental Protection Agency (EPA) published new regulations to regulate the disposal of CCRs at electric generating facilities. See Note 14 under the heading Solid Waste for additional information regarding the CCR rule. The CCR rule represents legal obligations of Great Plains Energy and KCP&L as to the closure and post-closure of its ponds and landfills containing CCRs. As a result of the CCR rule, Great Plains Energy and KCP&L increased their AROs $69.5 million and $51.3 million, respectively, in the second quarter of 2015. The following table summarizes the change in Great Plains Energy's and KCP&L's AROs.
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- References No definition available.
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- Definition The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Pension Plans and Other Employee Benefits |
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| Compensation and Retirement Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pension Plans and Other Employee Benefits | 8. PENSION PLANS AND OTHER EMPLOYEE BENEFITS Great Plains Energy maintains defined benefit pension plans for the majority of KCP&L's and GMO's active and inactive employees, including officers, and its 47% ownership share of Wolf Creek Nuclear Operating Corporation (WCNOC) defined benefit plans. For the majority of employees, pension benefits under these plans reflect the employees' compensation, years of service and age at retirement; however, for union employees hired after October 1, 2013, the benefits are derived from a cash balance account formula. Effective in 2014, the non-union plan was closed to future employees. Great Plains Energy also provides certain post-retirement health care and life insurance benefits for substantially all retired employees of KCP&L, GMO and its 47% ownership share of WCNOC. KCP&L and GMO record pension and post-retirement expense in accordance with rate orders from the MPSC and KCC that allow the difference between pension and post-retirement costs under GAAP and costs for ratemaking to be recognized as a regulatory asset or liability. This difference between financial and regulatory accounting methods is due to timing and will be eliminated over the life of the plans. In 2014 and 2013, Great Plains Energy incurred pension settlement charges of $8.5 million and $4.9 million, respectively, as a result of accelerated pension distributions. The following pension benefits tables provide information relating to the funded status of all defined benefit pension plans on an aggregate basis as well as the components of net periodic benefit costs. For financial reporting purposes, the market value of plan assets is the fair value. For regulatory reporting purposes, a five-year smoothing of assets is used to determine fair value. Net periodic benefit costs reflect total plan benefit costs prior to the effects of capitalization and sharing with joint owners of power plants.
For financial reporting purposes, the estimated prior service cost and net loss for the defined benefit plans that will be amortized from accumulated other comprehensive income (OCI) or a regulatory asset into net periodic benefit cost in 2016 are $0.7 million and $51.8 million, respectively. For financial reporting purposes, net actuarial gains and losses are recognized on a rolling five-year average basis. For regulatory reporting purposes, net actuarial gains and losses are amortized over ten years. The estimated prior service cost and net gain for the other post-retirement benefit plans that will be amortized from accumulated OCI or a regulatory asset into net periodic benefit cost in 2016 are $1.2 million and $1.5 million, respectively. The accumulated benefit obligation (ABO) for all defined benefit pension plans was $1,017.6 million and $1,036.8 million at December 31, 2015, and 2014, respectively. Pension and other post-retirement benefit plans with the PBO, ABO or accumulated other post-retirement benefit obligation (APBO) in excess of the fair value of plan assets at year-end are detailed in the following table.
The GMO Supplemental Executive Retirement Plan (SERP) is reflected as an unfunded ABO of $22.9 million. Great Plains Energy has approximately $16.4 million of assets in a non-qualified trust for this plan as of December 31, 2015, and expects to fund future benefit payments from these assets. The expected long-term rate of return on plan assets represents Great Plains Energy's estimate of the long-term return on plan assets and is based on historical and projected rates of return for current and planned asset classes in the plans' investment portfolios. Assumed projected rates of return for each asset class were selected after analyzing historical experience and future expectations of the returns of various asset classes. Based on the target asset allocation for each asset class, the overall expected rate of return for the portfolios was developed and adjusted for the effect of projected benefits paid from plan assets and future plan contributions. The following tables provide the weighted-average assumptions used to determine benefit obligations and net costs.
*after tax Great Plains Energy expects to contribute $75.7 million to the pension plans in 2016 to meet Employee Retirement Income Security Act of 1974, as amended (ERISA) funding requirements and regulatory orders, the majority of which is expected to be paid by KCP&L. Great Plains Energy's funding policy is to contribute amounts sufficient to meet the ERISA funding requirements and MPSC and KCC rate orders plus additional amounts as considered appropriate; therefore, actual contributions may differ from expected contributions. Great Plains Energy also expects to contribute $5.1 million to other post-retirement benefit plans in 2016, the majority of which is expected to be paid by KCP&L. The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid through 2025.
Pension plan assets are managed in accordance with prudent investor guidelines contained in the ERISA requirements. The investment strategy supports the objective of the fund, which is to earn the highest possible return on plan assets within a reasonable and prudent level of risk. The portfolios are invested, and periodically rebalanced, to achieve targeted allocations of approximately 33% U.S. large cap and small cap equity securities, 20% international equity securities, 35% fixed income securities, 7% real estate, 1% commodities and 4% hedge funds. Fixed income securities include domestic and foreign corporate bonds, collateralized mortgage obligations and asset-backed securities, U.S. government agency, state and local obligations, U.S. Treasury notes and money market funds. The fair values of Great Plains Energy's pension plan assets at December 31, 2015 and 2014, by asset category are in the following tables.
(a) At December 31, 2015 and 2014, this category is comprised of $121.6 million and $78.1 million, respectively, of traded mutual funds valued at daily listed prices and $73.9 million and $125.5 million, respectively, of traded common stocks and exchange traded funds. At December 31, 2015 and 2014, this category also includes $30.5 million and $31.6 million, respectively, of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (b) At December 31, 2015 and 2014, this category is comprised of $34.2 million and $38.6 million, respectively, of traded mutual funds valued at daily listed prices and $75.5 million and $70.1 million, respectively, of traded American depository receipts, global depository receipts and ordinary shares. At December 31, 2015 and 2014, this category also includes $37.7 million and $38.6 million, respectively, of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (c) At December 31, 2015 and 2014, this category is comprised of $12.2 million and $7.7 million, respectively, of traded real estate investment trusts. At December 31, 2015 and 2014, this category also includes $33.7 million and $31.2 million, respectively, of institutional common/collective trust funds and a limited partnership valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (d) Consists of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (e) At December 31, 2015 and 2014, this category is comprised of $20.0 million and $22.3 million, respectively, of traded mutual funds valued at daily listed prices. At December 31, 2015 and 2014, this category also includes $40.4 million and $43.8 million, respectively, of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (f) At December 31, 2015 and 2014, this category is comprised of $103.0 million and $100.3 million, respectively, of corporate bonds, $2.9 million and $4.0 million, respectively, of collateralized mortgage obligations and $2.9 million and $4.7 million, respectively, of other asset-backed securities. (g) Consists of closely-held limited partnerships valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. Other post-retirement plan assets are also managed in accordance with prudent investor guidelines contained in the ERISA requirements. The investment strategy supports the objective of the funds, which is to preserve capital, maintain sufficient liquidity and earn a consistent rate of return. Other post-retirement plan assets are invested primarily in fixed income securities, which may include domestic and foreign corporate bonds, collateralized mortgage obligations and asset-backed securities, U.S. government agency, state and local obligations, U.S. Treasury notes and money market funds, as well as domestic and international equity funds. The fair values of Great Plains Energy's other post-retirement plan assets at December 31, 2015 and 2014, by asset category are in the following tables.
(a) At December 31, 2015 and 2014 this category is comprised of $0.1 million and $0.2 million, respectively, of traded mutual funds valued at daily listed prices. At December 31, 2015 and 2014 this category also includes $68.8 million and $72.8 million, respectively, of an institutional common/collective trust fund valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (b) At December 31, 2015 and 2014, this category is comprised of $12.6 million and $10.3 million, respectively, of corporate bonds, $0.6 million and $0.8 million, respectively, of collateralized mortgage obligations and $2.4 million and $1.9 million, respectively, of other asset-backed securities. Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plans. The cost trend assumed for 2015 and 2016 was 7.0% and 6.8%, respectively, with the rate declining through 2025 to the ultimate cost trend rate of 4.5%. The effects of a one-percentage point change in the assumed health care cost trend rates, holding all other assumptions constant, at December 31, 2015, are detailed in the following table.
Employee Savings Plans Great Plains Energy has defined contribution savings plans (401(k)) that cover substantially all employees. Great Plains Energy matches employee contributions, subject to limits. The annual cost of the plans was approximately $10.6 million in 2015, $9.7 million in 2014 and $9.6 million in 2013. KCP&L's annual cost of the plans was approximately $7.9 million in 2015, $7.1 million in 2014 and $7.0 million in 2013. |
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Equity Compensation |
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| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Equity Compensation | 9. EQUITY COMPENSATION Great Plains Energy's Long-Term Incentive Plan is an equity compensation plan approved by Great Plains Energy's shareholders. The Long-Term Incentive Plan permits the grant of restricted stock, restricted stock units, bonus shares, stock options, stock appreciation rights, limited stock appreciation rights, director shares, director deferred share units and performance shares to directors, officers and other employees of Great Plains Energy and KCP&L. The maximum number of shares of Great Plains Energy common stock that can be issued under the plan is 8.0 million. Common stock shares delivered by Great Plains Energy under the Long-Term Incentive Plan may be authorized but unissued, held in the treasury or purchased on the open market (including private purchases) in accordance with applicable securities laws. Great Plains Energy has a policy of delivering newly issued shares, or shares surrendered by Long-Term Incentive Plan participants for the withholding of taxes and held in treasury, or both, and does not expect to repurchase common shares during 2016 to satisfy performance share payments and director deferred share unit conversion. Forfeiture rates are based on historical forfeitures and future expectations and are reevaluated annually. The following table summarizes Great Plains Energy's and KCP&L's equity compensation expense and the associated income tax benefit.
Performance Shares The payment of performance shares is contingent upon achievement of specific performance goals over a stated period of time as approved by the Compensation and Development Committee of the Board. The number of performance shares ultimately paid can vary from the number of shares initially granted depending on Great Plains Energy's performance over stated performance periods. Compensation expense for performance shares is calculated by taking the change in fair value between reporting periods for the portion for which the requisite service has been rendered. Dividends are accrued over the vesting period and paid in cash based on the number of performance shares ultimately paid. The fair value of performance share awards is estimated using the market value of the Company's stock at the valuation date and a Monte Carlo simulation technique that incorporates assumptions for inputs of expected volatilities, dividend yield and risk-free rates. Expected volatility is based on daily stock price change during a historical period commensurate with the remaining term of the performance period of the grant. The risk-free rate is based upon the rate at the time of the evaluation for zero-coupon government bonds with a maturity consistent with the remaining performance period of the grant. The dividend yield is based on the most recent dividends paid and the actual closing stock price on the valuation date. For shares granted in 2015, inputs for expected volatility, dividend yield and risk-free rates ranged from 16%-17%, 3.72%-4.03% and 0.86%-1.02%, respectively. Performance share activity is summarized in the following table. Performance adjustment represents the number of shares of common stock related to performance shares ultimately issued that can vary from the number of performance shares initially granted depending on Great Plains Energy's performance over a stated period of time.
* weighted-average At December 31, 2015, the remaining weighted-average contractual term was 1.0 year. The weighted-average grant-date fair value of shares granted was $24.03, $28.78 and $24.17 in 2015, 2014 and 2013, respectively. At December 31, 2015, there was $5.9 million of total unrecognized compensation expense, net of forfeiture rates, related to performance shares granted under the Long-Term Incentive Plan, which will be recognized over the remaining weighted-average contractual term. The total fair value of performance shares earned and paid was $0.5 million, $2.8 million and $2.4 million in 2015, 2014 and 2013, respectively. Restricted Stock Restricted stock cannot be sold or otherwise transferred by the recipient prior to vesting and has a value equal to the fair market value of the shares on the issue date. Restricted stock shares vest over a stated period of time with accruing reinvested dividends subject to the same restrictions. Compensation expense, calculated by multiplying shares by the grant-date fair value related to restricted stock, is recognized over the stated vesting period. Restricted stock activity is summarized in the following table.
* weighted-average At December 31, 2015, the remaining weighted-average contractual term was 1.3 years. The weighted-average grant-date fair value of shares granted was $25.89, $25.70 and $22.47 in 2015, 2014 and 2013, respectively. At December 31, 2015, there was $2.4 million of total unrecognized compensation expense, net of forfeiture rates, related to nonvested restricted stock granted under the Long-Term Incentive Plan, which will be recognized over the remaining weighted-average contractual term. Total fair value of shares vested was $2.2 million, $1.9 million and $1.2 million in 2015, 2014 and 2013, respectively. Director Deferred Share Units Non-employee directors receive shares of Great Plains Energy's common stock as part of their annual retainer. Each director may elect to defer receipt of their shares by receiving Director Deferred Share Units that convert to shares of Great Plains Energy's common stock at the end of January in the year after they leave the Board or such other time as elected by each director. Director Deferred Share Units have a value equal to the market value of Great Plains Energy's common stock on the grant date with accruing dividends. Compensation expense, calculated by multiplying the director deferred share units by the related grant-date fair value, is recognized at the grant date. The total fair value of shares of Director Deferred Share Units issued was insignificant for 2015 and 2014. Director Deferred Share Units activity is summarized in the following table.
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- Definition The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Short-term Borrowings and Short-term Bank Lines of Credit |
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Dec. 31, 2015 | |
| Short-term Borrowings and Short-term Bank Lines of Credit [Abstract] | |
| Short-term Borrowings and Short-term Bank Lines of Credit [Text Block] | 10. SHORT-TERM BORROWINGS AND SHORT-TERM BANK LINES OF CREDIT Great Plains Energy's $200 Million Revolving Credit Facility Great Plains Energy's $200 million revolving credit facility with a group of banks expires in October 2019. The facility's terms permit transfers of unused commitments between this facility and the KCP&L and GMO facilities discussed below, with the total amount of the facility not exceeding $400 million at any one time. A default by Great Plains Energy or any of its significant subsidiaries on other indebtedness totaling more than $50.0 million is a default under the facility. Under the terms of this facility, Great Plains Energy is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the facility, not greater than 0.65 to 1.00 at all times. At December 31, 2015, Great Plains Energy was in compliance with this covenant. At December 31, 2015, Great Plains Energy had $10.0 million of outstanding cash borrowings at a weighted-average interest rate of 1.94% and had issued $0.2 million in letters of credit under the credit facility. At December 31, 2014, Great Plains Energy had $4.0 million of outstanding cash borrowings at a weighted-average interest rate of 1.69% and had issued no letters of credit under the credit facility. KCP&L's $600 Million Revolving Credit Facility and Commercial Paper KCP&L's $600 million revolving credit facility with a group of banks provides support for its issuance of commercial paper and other general corporate purposes and expires in October 2019. Great Plains Energy and KCP&L may transfer up to $200 million of unused commitments between Great Plains Energy's and KCP&L's facilities. A default by KCP&L on other indebtedness totaling more than $50.0 million is a default under the facility. Under the terms of this facility, KCP&L is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the facility, not greater than 0.65 to 1.00 at all times. At December 31, 2015, KCP&L was in compliance with this covenant. At December 31, 2015, KCP&L had $180.3 million of commercial paper outstanding at a weighted-average interest rate of 0.70%, had issued letters of credit totaling $2.7 million and had no outstanding cash borrowings under the credit facility. At December 31, 2014, KCP&L had $358.3 million of commercial paper outstanding at a weighted-average interest rate of 0.48%, had issued letters of credit totaling $2.7 million and had no outstanding cash borrowings under the credit facility. GMO's $450 Million Revolving Credit Facility and Commercial Paper GMO's $450 million revolving credit facility with a group of banks provides support for its issuance of commercial paper and other general corporate purposes and expires in October 2019. Great Plains Energy and GMO may transfer up to $200 million of unused commitments between Great Plains Energy's and GMO's facilities. A default by GMO or any of its significant subsidiaries on other indebtedness totaling more than $50.0 million is a default under the facility. Under the terms of this facility, GMO is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the facility, not greater than 0.65 to 1.00 at all times. At December 31, 2015, GMO was in compliance with this covenant. At December 31, 2015, GMO had $43.7 million of commercial paper outstanding at a weighted-average interest rate of 0.65%, had issued letters of credit totaling $2.5 million and had no outstanding cash borrowings under the credit facility. At December 31, 2014, GMO had no commercial paper outstanding, had issued letters of credit totaling $3.2 million and had no outstanding cash borrowings under the credit facility. |
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- References No definition available.
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- Definition The entire disclosure for short-term debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Long-Term Debt |
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| Long-Term Debt | 11. LONG-TERM DEBT Great Plains Energy's and KCP&L's long-term debt is detailed in the following table.
Amortization of Debt Expense Great Plains Energy's and KCP&L's amortization of debt expense is detailed in the following table.
KCP&L General Mortgage Bonds KCP&L has issued mortgage bonds under the General Mortgage Indenture and Deed of Trust dated December 1, 1986, as supplemented (Indenture). The Indenture creates a mortgage lien on substantially all of KCP&L's utility plant. Mortgage bonds totaling $510.5 million and $596.4 million were outstanding at December 31, 2015 and 2014, respectively. In March 2015, KCP&L repaid its $14.0 million secured Series 2005 EIRR bonds at maturity. In September 2015, KCP&L purchased in lieu of redemption its $50.0 million and $21.9 million secured EIRR Series 2005 bonds. As of December 31, 2015, the bonds were still outstanding, but were not reported as a liability on the balance sheet since they are being held by KCP&L. KCP&L has the ability to remarket these bonds to third parties whenever it determines market conditions are sufficiently attractive to do so. KCP&L Municipal Bond Insurance Policies KCP&L's secured Series 2005 EIRR bonds totaling $50.0 million and $21.9 million, respectively, are covered by a municipal bond insurance policy between KCP&L and Syncora Guarantee, Inc. (Syncora). The insurance agreements between KCP&L and Syncora provide for reimbursement by KCP&L for any amounts that Syncora pays under the municipal bond insurance policies. The insurance agreements contain a covenant that the indebtedness to total capitalization ratio of KCP&L and its consolidated subsidiaries will not be greater than 0.68 to 1.00. At December 31, 2015, KCP&L was in compliance with this covenant. KCP&L is also restricted from issuing additional bonds under its General Mortgage Indenture if, after giving effect to such additional bonds, the proportion of secured debt to total indebtedness would be more than 75%, or more than 50% if the long term rating for such bonds by Standard & Poor's or Moody's Investors Service would be at or below A- or A3, respectively. The insurance agreement covering the unsecured Series 2005 EIRR bonds also required KCP&L to provide collateral to Syncora in the form of $50.0 million of Mortgage Bonds Series 2005 EIRR Insurer due 2035 for KCP&L's obligations under the insurance agreement as a result of KCP&L issuing general mortgage bonds in 2009 (other than refunding of outstanding general mortgage bonds) that resulted in the aggregate amount of outstanding general mortgage bonds exceeding 10% of total capitalization. The bonds are not incremental debt for KCP&L but collateralize Syncora's claim on KCP&L if Syncora was required to meet its obligation under the insurance agreement. In the event of a default under the insurance agreements, Syncora may take any available legal or equitable action against KCP&L, including seeking specific performance of the covenants. KCP&L Senior Notes In August 2015, KCP&L issued, at a discount, $350.0 million of 3.65% unsecured Senior Notes, maturing in 2025. GMO First Mortgage Bonds GMO has issued mortgage bonds under the General Mortgage Indenture and Deed of Trust dated April 1, 1946, as supplemented. The Indenture creates a mortgage lien on substantially all of GMO's St. Joseph Light & Power division utility plant. Mortgage bonds totaling $6.8 million and $7.9 million, respectively, were outstanding at December 31, 2015 and 2014. GMO Senior Notes Under the terms of the note purchase agreement for GMO's Series A, B and C Senior Notes, GMO is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the agreement, not greater than 0.65 to 1.00 at all times. In addition, GMO's priority debt, as defined in the agreement, cannot exceed 15% of consolidated tangible net worth, as defined in the agreement. At December 31, 2015, GMO was in compliance with these covenants. Scheduled Maturities Great Plains Energy's and KCP&L's long-term debt maturities for the next five years are detailed in the following table.
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- References No definition available.
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- Definition The entire disclosure for long-term debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Common Shareholders' Equity |
12 Months Ended |
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Dec. 31, 2015 | |
| Stockholders' Equity Note [Abstract] | |
| Common Shareholders' Equity | 12. COMMON SHAREHOLDERS' EQUITY Great Plains Energy has an effective shelf registration statement for the sale of unlimited amounts of securities with the Securities and Exchange Commission (SEC) that became effective in March 2015 and expires in March 2018. Great Plains Energy has 7.0 million shares of common stock registered with the SEC for its Dividend Reinvestment and Direct Stock Purchase Plan. The plan allows for the purchase of common shares by reinvesting dividends or making optional cash payments. Great Plains Energy can issue new shares or purchase shares on the open market for the plan. At December 31, 2015, 2.1 million shares remained available for future issuances. Great Plains Energy has 14.3 million shares of common stock registered with the SEC for a defined contribution savings plan (401(k)). Shares issued under the plan may be either newly issued shares or shares purchased in the open market. At December 31, 2015, 1.0 million shares remained available for future issuances. Treasury shares are held for future distribution upon issuance of shares in conjunction with the Company's Long-Term Incentive Plan. Great Plains Energy's articles of incorporation restrict the payment of common stock dividends in the event common equity is 25% or less of total capitalization. In addition, if preferred stock dividends are not declared and paid when scheduled, Great Plains Energy could not declare or pay common stock dividends or purchase any common shares. If the unpaid preferred stock dividends equal four or more full quarterly dividends, the preferred shareholders, voting as a single class, could elect the smallest number of directors necessary to constitute a majority of the full Board. Certain conditions in the MPSC and KCC orders authorizing the holding company structure require Great Plains Energy and KCP&L to maintain consolidated common equity of at least 30% and 35%, respectively, of total capitalization (including only the amount of short-term debt in excess of the amount of construction work in progress). Under the Federal Power Act, KCP&L and GMO generally can pay dividends only out of retained earnings. The revolving credit agreements of Great Plains Energy, KCP&L and GMO and the note purchase agreement for GMO's Series A, B and C Senior Notes contain a covenant requiring the respective company to maintain a consolidated indebtedness to consolidated total capitalization ratio of not more than 0.65 to 1.00 at all times. As of December 31, 2015, all of Great Plains Energy's and KCP&L's retained earnings and net income were free of restrictions. As a result of the above restrictions, Great Plains Energy's subsidiaries had restricted net assets of approximately $2.8 billion as of December 31, 2015. The restrictions are not expected to affect the Companies' ability to pay dividends at the current level in the foreseeable future. |
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- References No definition available.
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- Definition The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Preferred Stock |
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Dec. 31, 2015 | |
| Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract] | |
| Preferred Stock [Text Block] | 13. PREFERRED STOCK At December 31, 2015, 1.6 million shares of Cumulative No Par Preferred Stock, 390,000 shares of Cumulative Preferred Stock, $100 par value and 11.0 million shares of no par Preference Stock were authorized under Great Plains Energy's articles of incorporation. All of the 390,000 authorized shares of Cumulative Preferred Stock are issued and outstanding. Great Plains Energy has the option to redeem the $39.0 million of issued Cumulative Preferred Stock at prices ranging from 101% to 103.7% of par value. If Great Plains Energy voluntarily files for dissolution or liquidation, the Cumulative Preferred Stock holders are entitled to receive the redemption prices. If a proceeding for dissolution or liquidation is filed against Great Plains Energy, the Cumulative Preferred Stock holders are entitled to receive the $100 par value per share plus accrued and unpaid dividends. |
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- References No definition available.
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- Definition The entire disclosure for terms, amounts, nature of changes, rights and privileges, dividends, and other matters related to preferred stock. No definition available.
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Commitments and Contingencies |
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| Commitments and Contingencies Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Commitments and Contingencies | 14. COMMITMENTS AND CONTINGENCIES Environmental Matters Great Plains Energy and KCP&L are subject to extensive federal, state and local environmental laws, regulations and permit requirements relating to air and water quality, waste management and disposal, natural resources and health and safety. In addition to imposing continuing compliance obligations and remediation costs, these laws, regulations and permits authorize the imposition of substantial penalties for noncompliance, including fines, injunctive relief and other sanctions. The cost of complying with current and future environmental requirements is expected to be material to Great Plains Energy and KCP&L. Failure to comply with environmental requirements or to timely recover environmental costs through rates could have a material effect on Great Plains Energy's and KCP&L's results of operations, financial position and cash flows. Great Plains Energy's and KCP&L's current estimates of capital expenditures (exclusive of AFUDC) and property taxes) over the next five years to comply with environmental regulations are in the following table. The total cost of compliance with any existing, proposed or future laws and regulations may be significantly different from these cost estimates provided.
The Companies expect to seek recovery of the costs associated with environmental requirements through rate increases; however, there can be no assurance that such rate increases would be granted. The Companies may be subject to materially adverse rate treatment in response to competitive, economic, political, legislative or regulatory factors and/or public perception of the Companies' environmental reputation. The following discussion groups environmental and certain associated matters into the broad categories of air and climate change, water, solid waste and remediation. Clean Air Act and Climate Change Overview The Clean Air Act Amendments of 1990 (Clean Air Act) and associated regulations enacted by the EPA form a comprehensive program to preserve and enhance air quality. States are required to establish regulations and programs to address all requirements of the Clean Air Act and have the flexibility to enact more stringent requirements. All of Great Plains Energy's and KCP&L's generating facilities, and certain of their other facilities, are subject to the Clean Air Act. Mercury and Air Toxics Standards (MATS) Rule In December 2011, the EPA finalized the MATS Rule that will reduce emissions of toxic air pollutants, also known as hazardous air pollutants, from new and existing coal- and oil-fired electric utility generating units with a capacity of greater than 25 MWs. The rule establishes numerical emission limits for mercury, particulate matter (a surrogate for non-mercury metals) and hydrochloric acid (a surrogate for acid gases). The rule establishes work practices, instead of numerical emission limits, for organic air toxics, including dioxin/furan. KCP&L’s and GMO’s affected coal-fired units currently comply or will be compliant in April 2016. Estimated capital costs to comply with the MATS Rule are included in the estimated capital expenditures table above. Industrial Boiler Rule In December 2012, the EPA issued a final rule that would reduce emissions of hazardous air pollutants from new and existing industrial boilers. The final rule establishes numeric emission limits for mercury, particulate matter (as a surrogate for non-mercury metals), hydrogen chloride (as a surrogate for acid gases) and carbon monoxide (as a surrogate for non-dioxin organic hazardous air pollutants). The final rule establishes emission limits for KCP&L's and GMO's existing units that produce steam other than for the generation of electricity. The final rule does not apply to KCP&L's and GMO's electricity generating boilers, but would apply to most of GMO's Lake Road boilers, which also serve steam customers, and to auxiliary boilers at other generating facilities. KCP&L’s and GMO’s affected units currently comply or will be compliant in January 2017. Estimated capital costs to comply with the Industrial Boiler Rule are included in the estimated capital expenditures table above. Climate Change The Companies' current generation capacity is primarily coal-fired and is estimated to produce about one ton of carbon dioxide (CO2) per MWh, or approximately 21 million tons and 15 million tons per year for Great Plains Energy and KCP&L, respectively. The Companies are subject to existing greenhouse gas reporting regulations and certain greenhouse gas requirements. Federal or state legislation concerning the reduction of emissions of greenhouse gases, including CO2, could be enacted in the future. At the international level, in December 2015 the Paris Agreement was adopted by nearly 200 countries. The Paris Agreement did not result in any new, legally binding obligations on the United States to meet a particular greenhouse gas emissions target, but establishes a framework for international cooperation on climate change. International agreements legally binding on the United States may be reached in the future. Greenhouse gas legislation has the potential of having significant financial and operational impacts on Great Plains Energy and KCP&L; however, the ultimate financial and operational consequences to Great Plains Energy and KCP&L cannot be determined until such legislation is passed. In the absence of new Congressional mandates, the EPA is proceeding with the regulation of greenhouse gases under the existing Clean Air Act. In August 2015, the EPA finalized CO2 emission standards for new, modified and reconstructed affected fossil-fuel-fired electric utility generating units. The standards would not apply to Great Plains Energy's and KCP&L's existing units unless the units were modified or reconstructed in the future. In August 2015, the EPA finalized its Clean Power Plan which sets CO2 emission performance rates for existing affected fossil fuel-fired electric generating units. Specifically, the EPA translated those performance rates into a state goal measured in mass and rate based on each state’s generation mix. The states have the ability to develop their own plans for affected units to achieve either the performance rates directly or the state goals, with guidelines for the development, submittal and implementation of those plans. Nationwide, by 2030, the EPA projects the Clean Power Plan would achieve CO2 emission reductions from the power sector of approximately 32% from CO2 emission levels in 2005. The EPA has finalized an interim CO2 goal rate reduction in Kansas and Missouri (average of 2022-2029) of 34% and 26%, respectively, and 2030 targets in Kansas and Missouri of 44% and 37%, respectively. The baseline for these reductions is 2012 CO2 emissions adjusted by the EPA. The EPA has also finalized mass based CO2 reduction goals. States are required to submit plans to implement the Clean Power Plan. An EPA plan with either a rate-based or mass-based trading program has yet to be finalized and can be enforced in states that fail to submit approved plans. In February 2016, the U.S. Supreme Court granted a stay of the Clean Power Plan putting the rule on hold pending review in the United States Court of Appeals for the District of Columbia Circuit and any subsequent review by the U.S. Supreme Court if such review is sought. Compliance with the Clean Power Plan has the potential of having significant financial and operational impacts on Great Plains Energy and KCP&L; however, the ultimate financial and operational consequences to Great Plains Energy and KCP&L cannot be determined until the outcome of pending litigation is known and/or the state plans to implement the Clean Power Plan are known. The Companies are subject to existing renewable energy standards in Missouri. Management believes that national renewable energy standards are also possible. The timing, provisions and impact of such possible future requirements, including the cost to obtain and install new equipment to achieve compliance, cannot be reasonably estimated at this time. Clean Water Act The Clean Water Act and associated regulations enacted by the EPA form a comprehensive program to restore and preserve water quality. Like the Clean Air Act, states are required to establish regulations and programs to address all requirements of the Clean Water Act, and have the flexibility to enact more stringent requirements. All of Great Plains Energy's and KCP&L's generating facilities, and certain of their other facilities, are subject to the Clean Water Act. In May 2014, the EPA finalized regulations pursuant to Section 316(b) of the Clean Water Act regarding cooling water intake structures pursuant to a court approved settlement. KCP&L generation facilities with cooling water intake structures are subject to the best technology available standards based on studies completed to comply with such standards. The rule provides flexibility to work with the states to develop the best technology available to minimize aquatic species impacted by being pinned against intake screens (impingement) or drawn into cooling water systems (entrainment). Estimated costs to comply with Section 316(b) of the Clean Water Act are included in the estimated capital expenditures table above. KCP&L holds a permit from the Missouri Department of Natural Resources (MDNR) covering water discharge from its Hawthorn Station. The permit authorizes KCP&L to, among other things, withdraw water from the Missouri River for cooling purposes and return the heated water to the Missouri River. KCP&L has applied for a renewal of this permit and the EPA has submitted an interim objection letter regarding the allowable amount of heat that can be contained in the returned water. Until this matter is resolved, KCP&L continues to operate under its current permit. Future water permit renewals at KCP&L's Iatan Station and at GMO's Sibley and Lake Road Stations could also be impacted by the allowable amount of heat that can be contained in the returned water. Great Plains Energy and KCP&L cannot predict the outcome of these matters; however, while less significant outcomes are possible, these matters may require a reduction in generation, installation of cooling towers or other technology to cool the water, or both, any of which could have a significant impact on Great Plains Energy's and KCP&L's results of operations, financial position and cash flows. In September 2015, the EPA finalized a revision of the technology-based effluent limitations guidelines and standards regulation to make the existing controls on discharges from steam electric power plants more stringent. The final rule sets the first federal limits on the levels of toxic metals in wastewater that can be discharged from power plants. The new requirements for existing power plants would be phased in between 2018 and 2023. The final rule establishes new or additional requirements for wastewaters associated with the following processes and byproducts at certain KCP&L and GMO stations: flue gas desulfurization, fly ash, bottom ash, flue gas mercury control, and combustion residual leachate from landfills and surface impoundments. Estimated capital costs to comply with the final rule are included in the estimated capital expenditures table above. Solid Waste Solid and hazardous waste generation, storage, transportation, treatment and disposal are regulated at the federal and state levels under various laws and regulations. In December 2014, the EPA finalized regulations to regulate CCRs under the Resource Conservation and Recovery Act (RCRA) subtitle D to address the risks from the disposal of CCRs generated from the combustion of coal at electric generating facilities. The Companies use coal in generating electricity and dispose of the CCRs in both on-site facilities and facilities owned by third parties. The rule requires periodic assessments; groundwater monitoring; location restrictions; design and operating requirements; recordkeeping and notifications; and closure, among other requirements, for CCR units. The rule was promulgated in the Federal Register on April 17, 2015, and became effective six months after promulgation with various obligations effective at specified times within the rule. Estimated capital costs to comply with the CCR rule are included in the estimated capital expenditures table above. See Note 7 for information regarding an increase in Great Plains Energy's and KCP&L's AROs as a result of the CCR rule. Remediation Certain federal and state laws, including the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), hold current and previous owners or operators of contaminated facilities and persons who arranged for the disposal or treatment of hazardous substances liable for the cost of investigation and cleanup. CERCLA and other laws also authorize the EPA and other agencies to issue orders compelling potentially responsible parties to clean up sites that are determined to present an actual or potential threat to human health or the environment. GMO is named as a potentially responsible party at a disposal site for polychlorinated biphenyl (PCB) contamination, and retains some environmental liability for several operations and investments it no longer owns. In addition, GMO also owns, or has acquired liabilities from companies that once owned or operated, former manufactured gas plant (MGP) sites, which are subject to the supervision of the EPA and various state environmental agencies. At December 31, 2015, and 2014, KCP&L had $0.3 million accrued for environmental remediation expenses, which covers ground water monitoring at a former MGP site. The amount accrued was established on an undiscounted basis and KCP&L does not currently have an estimated time frame over which the accrued amount may be paid. In addition to the $0.3 million accrual above, at December 31, 2015, and 2014, Great Plains Energy had $1.4 million accrued for the future investigation and remediation of certain additional GMO identified MGP sites and retained liabilities. This estimate was based upon review of the potential costs associated with conducting investigative and remedial actions at identified sites, as well as the likelihood of whether such actions will be necessary. This estimate could change materially after further investigation, and could also be affected by the actions of environmental agencies and the financial viability of other potentially responsible parties; however, given the uncertainty of these items the possible loss or range of loss in excess of the amount accrued is not estimable. GMO has pursued recovery of remediation costs from insurance carriers and other potentially responsible parties. As a result of a settlement with an insurance carrier, approximately $1.4 million in insurance proceeds less an annual deductible is available to GMO to recover qualified MGP remediation expenses. GMO would seek recovery of additional remediation costs and expenses through rate increases; however, there can be no assurance that such rate increases would be granted. Contractual Commitments Great Plains Energy's and KCP&L's expenses related to lease commitments are detailed in the following table.
Great Plains Energy's and KCP&L's contractual commitments at December 31, 2015, excluding pensions and long-term debt, are detailed in the following tables.
Great Plains Energy's and KCP&L's lease commitments end in 2048. Operating lease commitments include rail cars to serve jointly-owned generating units where KCP&L is the managing partner. Of the amounts included in the table above, KCP&L will be reimbursed by the other owners for approximately $1.5 million in 2016 , $0.9 million in 2017 and approximately $0.4 million per year from 2018 to 2025, for a total of $6.0 million. Fuel commitments consist of commitments for nuclear fuel, coal and coal transportation. Power commitments consist of commitments for renewable energy under power purchase agreements. KCP&L and GMO purchase capacity from other utilities and nonutility suppliers. Purchasing capacity provides the option to purchase energy if needed or when market prices are favorable. KCP&L has capacity sales agreements not included above that total $6.0 million, $1.9 million, $2.1 million, $1.9 million and $2.0 million per year from 2016 to 2020, respectively. Non-regulated natural gas transportation consists of MPS Merchant's commitments. Other represents individual commitments entered into in the ordinary course of business. |
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- Definition The entire disclosure for commitments and contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Legal Proceedings |
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| Legal Proceedings [Abstract] | |
| Contingencies Disclosure [Text Block] | 15. LEGAL PROCEEDINGS GMO Western Energy Crisis In response to complaints of excessive prices in the California energy markets, FERC issued an order in July 2001 requiring net sellers of power in the California markets from October 2, 2000, through June 20, 2001, at prices above a FERC-determined competitive market clearing price, to make refunds to net purchasers of power in the California market during that time period. Because MPS Merchant was a net purchaser of power during the refund period, it has received approximately $8 million in refunds through settlements with certain sellers of power. MPS Merchant estimates that it is entitled to approximately $12 million in additional refunds under the standards FERC has used in this case once a comprehensive resettlement of those markets occurs, as required by FERC. FERC has stated that interest will be applied to the refunds but the amount of interest has not yet been determined. In December 2001, various parties appealed FERC orders to the United States Court of Appeals for the Ninth Circuit (Ninth Circuit) seeking review of a number of issues, including expansion of the refund period to include periods prior to October 2, 2000 (the Summer Period). MPS Merchant was a net seller of power during the Summer Period. On August 2, 2006, the Ninth Circuit issued an order finding, among other things, that FERC erred in failing to consider certain legal issues regarding whether it has authority to order refunds for violation of FERC-approved tariffs during the Summer Period. The court remanded the matter to FERC for further consideration. In November 2014 FERC issued an order finding that MPS Merchant engaged in tariff violations during the Summer Period and ordering refunds in the form of disgorgement of certain revenues. MPS Merchant (and other parties) filed a request for rehearing challenging FERC's findings of tariff violations and the remedy imposed in the November 2014 order. Additionally, several parties representing California utilities and governmental agencies filed a request for clarification or rehearing focusing on the remedy. In November 2015, FERC issued an order on rehearing, confirming its findings of violation and expanding the remedy from its November 2014 order to cover additional MPS Merchant sales in the California markets. MPS Merchant filed another request for rehearing, challenging the expanded remedy, and also filed a petition for review of the November 2014 and November 2015 orders with the Ninth Circuit. In February 2016, FERC issued another order on rehearing/clarification that requires MPS Merchant to refund, in the form of disgorgement, all revenues in excess of the FERC-determined competitive market clearing price for all sales in the California markets during the Summer Period that occurred in any hour in which any remaining respondent in the proceeding was found to have committed a tariff violation. That order is subject to further rehearing and judicial review. Under FERC's orders, MPS Merchant may be able to offset its costs of selling power against any remedy ultimately imposed to ensure that it does not under-recover its actual costs. Due to the uncertainties remaining in the case, the loss or range of loss cannot be reasonably estimated. |
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- Definition The entire disclosure for loss and gain contingencies. Describes any existing condition, situation, or set of circumstances involving uncertainty as of the balance sheet date (or prior to issuance of the financial statements) as to a probable or reasonably possible loss incurred by an entity that will ultimately be resolved when one or more future events occur or fail to occur, and typically discloses the amount of loss recorded or a range of possible loss, or an assertion that no reasonable estimate can be made. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Guarantees |
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| Guarantees [Text Block] | 16. GUARANTEES In the ordinary course of business, Great Plains Energy and certain of its subsidiaries enter into various agreements providing financial or performance assurance to third parties on behalf of certain subsidiaries. Such agreements include, for example, guarantees and letters of credit. These agreements are entered into primarily to support or enhance the creditworthiness otherwise attributed to a subsidiary on a stand-alone basis, thereby facilitating the extension of sufficient credit to accomplish the subsidiary's intended business purposes. The majority of these agreements guarantee the Company's own future performance, so a liability for the fair value of the obligation is not recorded. At December 31, 2015, Great Plains Energy has provided $138.4 million of credit support for GMO as follows:
Great Plains Energy has also guaranteed GMO's commercial paper program. At December 31, 2015, GMO had $43.7 million commercial paper outstanding. |
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- Definition The entire disclosure for each guarantee obligation, or each group of similar guarantee obligations, including (a) the nature of the guarantee, including its term, how it arose, and the events or circumstances that would require the guarantor to perform under the guarantee; (b) the maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee; (c) the current carrying amount of the liability, if any, for the guarantor's obligations under the guarantee; and (d) the nature of any recourse provisions under the guarantee, and any assets held either as collateral or by third parties, and any relevant related party disclosure. Excludes disclosures about product warranties. No definition available.
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Related Party Transactions and Relationships |
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| Related Party Transactions and Relationships | 17. RELATED PARTY TRANSACTIONS AND RELATIONSHIPS KCP&L employees manage GMO's business and operate its facilities at cost, including GMO's 18% ownership interest in KCP&L's Iatan Nos. 1 and 2. The operating expenses and capital costs billed from KCP&L to GMO were $183.6 million for 2015, $173.9 million for 2014 and $223.6 million for 2013. Additionally, KCP&L and GMO engage in wholesale electricity transactions with each other. KCP&L's net wholesale sales to GMO were $0.2 million, $12.7 million and $25.6 million in 2015, 2014 and 2013, respectively. KCP&L and GMO are also authorized to participate in the Great Plains Energy money pool, an internal financing arrangement in which funds may be lent on a short-term basis to KCP&L and GMO from Great Plains Energy and between KCP&L and GMO. At December 31, 2014, KCP&L had a money pool payable to GMO of $12.6 million. The following table summarizes KCP&L's related party net receivables.
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- References No definition available.
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- Definition The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Instruments |
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| Derivative Instruments and Hedging Activities Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Derivative Instruments and Hedging Activities Disclosure [Text Block] | 18. DERIVATIVE INSTRUMENTS Great Plains Energy and KCP&L are exposed to a variety of market risks including interest rates and commodity prices. Management has established risk management policies and strategies to reduce the potentially adverse effects that the volatility of the markets may have on Great Plains Energy's and KCP&L's operating results. Great Plains Energy's and KCP&L's interest rate risk management activities have included using derivative instruments to hedge against future interest rate fluctuations on anticipated debt issuances. Commodity risk management activities, including the use of certain derivative instruments, are subject to the management, direction and control of an internal commodity risk committee. Management maintains commodity price risk management strategies that use derivative instruments to reduce the effects of fluctuations in wholesale sales, fuel and purchased power expense caused by commodity price volatility. Counterparties to commodity derivatives expose Great Plains Energy and KCP&L to credit loss in the event of nonperformance. This credit loss is limited to the cost of replacing these contracts at current market rates. Derivative instruments, excluding those instruments that qualify for the NPNS election, which are accounted for by accrual accounting, are recorded on the balance sheet at fair value as an asset or liability. Changes in the fair value of derivative instruments are recorded to a regulatory asset or liability consistent with KCC and MPSC regulatory orders. Great Plains Energy and KCP&L have posted collateral, in the ordinary course of business, for the aggregate fair value of all derivative instruments with credit risk-related contingent features that are in a liability position. At December 31, 2015, Great Plains Energy and KCP&L have posted collateral in excess of the aggregate fair value of their derivative instruments; therefore, if the credit risk-related contingent features underlying these agreements were triggered, Great Plains Energy and KCP&L would not be required to post additional collateral to their counterparties. For derivative contracts with counterparties under master netting arrangements, Great Plains Energy and KCP&L can net receivables and payables with each respective counterparty. Commodity Risk Management KCP&L's risk management policy uses derivative instruments to mitigate exposure to market price fluctuations for wholesale power. KCP&L has designated these financial contracts as economic hedges (non-hedging derivatives). The fair values of these instruments are recorded as derivative assets or liabilities with an offsetting entry recorded to a regulatory asset or liability. The settlement costs are included in KCP&L's fuel recovery mechanisms. A regulatory asset or liability is recorded to reflect the change in the timing of recognition authorized by KCC and MPSC. Recovery of actual costs will not impact earnings, but will impact cash flows due to the timing of the recovery mechanism. KCP&L and GMO have Transmission Congestion Rights (TCRs) that they utilize to hedge against congestion costs and protect load prices in the Southwest Power Pool, Inc. (SPP) Integrated Marketplace. These financial contracts have been designated as economic hedges (non-hedging derivatives). The fair values of these instruments are recorded as derivative assets or liabilities with an offsetting entry recorded to a regulatory asset or liability. The settlement costs are included in KCP&L's and GMO's fuel recovery mechanisms. A regulatory asset or liability is recorded to reflect the change in the timing of recognition authorized by KCC and MPSC. Recovery of actual costs will not impact earnings, but will impact cash flows due to the timing of the recovery mechanism. GMO's risk management policy uses derivative instruments to mitigate price exposure to natural gas price volatility in the market. At December 31, 2015, GMO had financial contracts in place to hedge approximately 66%, 18% and 8% of the expected on-peak natural gas generation and natural gas equivalent purchased power price exposure for 2016, 2017 and 2018, respectively. The fair value of the portfolio will settle against actual purchases of natural gas and purchased power. GMO has designated its natural gas hedges as economic hedges (non-hedging derivatives). In connection with GMO's 2005 Missouri electric rate case, it was agreed that the settlement costs of these contracts would be recognized in fuel expense. The settlement cost is included in GMO's fuel recovery mechanism. A regulatory asset or liability is recorded to reflect the change in the timing of recognition authorized by the MPSC. Recovery of actual costs will not impact earnings, but will impact cash flows due to the timing of the recovery mechanism. MPS Merchant, which has certain long-term natural gas contracts remaining from its former non-regulated trading operations, manages the daily delivery of its remaining contractual commitments with economic hedges (non-hedging derivatives) to reduce its exposure to changes in market prices. Within the trading portfolio, MPS Merchant takes certain positions to hedge physical sale or purchase contracts. MPS Merchant records the fair value of physical trading energy contracts as derivative assets or liabilities with an offsetting entry to the consolidated statements of comprehensive income. The gross notional contract amount and recorded fair values of open positions for derivative instruments are summarized in the following table. The fair values of these derivatives are recorded on the consolidated balance sheets. The fair values below are gross values before netting agreements and netting of cash collateral.
The fair values of Great Plains Energy's and KCP&L's open derivative positions and balance sheet classification are summarized in the following tables. The fair values below are gross values before netting agreements and netting of cash collateral.
The following tables provide information regarding Great Plains Energy's and KCP&L's offsetting of derivative assets and liabilities.
At December 31, 2015, and 2014, Great Plains Energy offset $5.7 million and $2.3 million, respectively, of cash collateral posted with counterparties against net derivative positions. See Note 20 for information regarding amounts reclassified out of accumulated other comprehensive loss for Great Plains Energy and KCP&L. Great Plains Energy's accumulated OCI at December 31, 2015, includes $9.2 million that is expected to be reclassified to expenses over the next twelve months. KCP&L's accumulated OCI at December 31, 2015, includes $8.8 million that is expected to be reclassified to expenses over the next twelve months. The following tables summarize the amounts of gain (loss) recognized for the change in fair value of commodity contract derivatives not designated as hedging instruments for Great Plains Energy and KCP&L.
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- References No definition available.
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- Definition The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements |
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| Fair Value Disclosures [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Fair Value Measurements | 19. FAIR VALUE MEASUREMENTS GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. GAAP establishes a fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value into three broad categories, giving the highest priority to quoted prices in active markets for identical assets or liabilities and lowest priority to unobservable inputs. A definition of the various levels, as well as discussion of the various measurements within the levels, is as follows: Level 1 – Unadjusted quoted prices for identical assets or liabilities in active markets that Great Plains Energy and KCP&L have access to at the measurement date. Level 2 – Market-based inputs for assets or liabilities that are observable (either directly or indirectly) or inputs that are not observable but are corroborated by market data. Level 3 – Unobservable inputs, reflecting Great Plains Energy's and KCP&L's own assumptions about the assumptions market participants would use in pricing the asset or liability. Great Plains Energy and KCP&L record cash and cash equivalents and short-term borrowings on the balance sheet at cost, which approximates fair value due to the short-term nature of these instruments. Great Plains Energy and KCP&L record long-term debt on the balance sheet at amortized cost. The fair value of long-term debt is measured as a Level 2 liability and is based on quoted market prices, with the incremental borrowing rate for similar debt used to determine fair value if quoted market prices are not available. At December 31, 2015, the book value and fair value of Great Plains Energy's long-term debt, including current maturities, were $3.7 billion and $4.0 billion, respectively. At December 31, 2014, the book value and fair value of Great Plains Energy's long-term debt, including current maturities, were $3.5 billion and $3.8 billion, respectively. At December 31, 2015, the book value and fair value of KCP&L's long-term debt, including current maturities, were $2.6 billion and $2.8 billion, respectively. At December 31, 2014, the book value and fair value of KCP&L's long-term debt, including current maturities, were $2.3 billion and $2.6 billion, respectively. The following tables include Great Plains Energy's and KCP&L's balances of financial assets and liabilities measured at fair value on a recurring basis. The fair values below are gross values before netting arrangements and netting of cash collateral.
The following tables reconcile the beginning and ending balances for all Level 3 assets and liabilities measured at fair value on a recurring basis.
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- References No definition available.
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- Definition The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Accumulated Other Comprehensive Income (Loss) |
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| Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accumulated Other Comprehensive Income (Loss) [Text Block] | 20. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The following tables reflect the change in the balances of each component of accumulated other comprehensive loss for Great Plains Energy and KCP&L.
(a) Net of tax
The following tables reflect the effect on certain line items of net income from amounts reclassified out of each component of accumulated other comprehensive loss for Great Plains Energy and KCP&L.
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- References No definition available.
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- Definition The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Taxes |
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| Income Tax Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Income Tax Disclosure [Text Block] | 21. TAXES Components of income tax expense are detailed in the following tables.
Effective Income Tax Rates Effective income tax rates reflected in the financial statements and the reasons for their differences from the statutory federal rates are detailed in the following tables.
Deferred Income Taxes The tax effects of major temporary differences resulting in deferred income tax assets (liabilities) in the consolidated balance sheets are in the following tables.
(a) Reflects adoption of ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes. See Note 1 to the consolidated financial statements under the heading New Accounting Standards for additional information.
Tax Credit Carryforwards At December 31, 2015 and 2014, Great Plains Energy had $169.2 million and $155.1 million, respectively, of federal general business income tax credit carryforwards. At December 31, 2015 and 2014, KCP&L had $166.6 million and $153.2 million, respectively, of federal general business income tax credit carryforwards. The carryforwards for both Great Plains Energy and KCP&L relate primarily to Advanced Coal Investment Tax Credits and Wind Production tax credits and expire in the years 2028 to 2035. Approximately $0.5 million of Great Plains Energy's credits are related to Low Income Housing credits that were acquired in the GMO acquisition. Due to federal limitations on the utilization of income tax attributes acquired in the GMO acquisition, management expects a portion of these credits to expire unutilized and has provided a valuation allowance against $0.4 million of the federal income tax benefit. At December 31, 2015 and 2014, Great Plains Energy had $87.6 million of federal alternative minimum tax credit carryforwards, all of which was acquired in the GMO acquisition. These credits do not expire and can be used to reduce taxes paid in the future. Net Operating Loss Carryforwards At December 31, 2015 and 2014, Great Plains Energy had $656.1 million and $521.0 million, respectively, of tax benefits related to federal net operating loss (NOL) carryforwards. Approximately $313.2 million at December 31, 2015 and 2014 are tax benefits related to NOLs that were acquired in the GMO acquisition. The tax benefits for NOLs originating in 2003 are $30.1 million, $152.4 million originating in 2004, $74.1 million originating in 2005, $53.3 million originating in 2006, $1.3 million originating in 2007, $2.4 million originating in 2008, $36.5 million originating in 2009, $4.1 million originating in 2010 and $109.7 million originating in 2011, $2.5 million originating in 2012, $2.3 million originating in 2013, $86.3 million originating in 2014 and $101.1 million originating in 2015. The federal NOL carryforwards expire in years 2023 to 2035. The Company expects a portion of these NOLs to expire unutilized and has provided a valuation allowance against $0.9 million of federal tax benefits. In addition, Great Plains Energy also had deferred tax benefits of $78.8 million and $65.9 million related to state NOLs as of December 31, 2015 and 2014, respectively. Of these amounts, approximately $39.2 million and $40.7 million at December 31, 2015 and 2014, respectively, were acquired in the GMO acquisition. Management does not expect to utilize $18.6 million of NOLs in state tax jurisdictions where the Company does not expect to operate in the future. Therefore, a valuation allowance has been provided against $18.6 million of state tax benefits. Valuation Allowances Great Plains Energy is required to assess the ultimate realization of deferred tax assets using a “more likely than not” assessment threshold. This assessment takes into consideration tax planning strategies within Great Plains Energy's control. As a result of this assessment, Great Plains Energy has established a partial valuation allowance for federal and state tax NOL carryforwards and tax credit carryforwards. During 2015, $3.3 million of tax expense was recorded in continuing operations primarily related to state NOL carryforwards that the Company expects to expire unutilized due to the extension of bonus depreciation through 2019. Uncertain Tax Positions At December 31, 2015 and 2014, Great Plains Energy had $2.3 million and $2.6 million, respectively, of liabilities related to unrecognized tax benefits. Of these amounts, $0.3 million at December 31, 2015 and 2014, respectively, is expected to impact the effective tax rate if recognized. At December 31, 2013, Great Plains Energy had $9.8 million of liabilities related to unrecognized tax benefits of which $6.5 million was expected to impact the effective tax rate if recognized. The $7.2 million decrease in unrecognized tax benefits is primarily due to a decrease of $6.1 million of unrecognized tax benefits were related to former GMO non-regulated operations. The following table reflects activity for Great Plains Energy related to the liability for unrecognized tax benefits.
Great Plains Energy recognizes interest related to unrecognized tax benefits in interest expense and penalties in non-operating expenses. At December 31, 2015, 2014 and 2013, amounts accrued for interest related to unrecognized tax benefits for Great Plains Energy were none, none and $3.2 million, respectively. At December 31, 2015, 2014 and 2013, amounts accrued for penalties with respect to unrecognized tax benefits for Great Plains Energy were none, none and $0.6 million, respectively. In 2015, 2014 and 2013, Great Plains Energy recognized a decrease of none, $3.2 million and $0.1 million, respectively, of interest expense related to unrecognized tax benefits. The Company is unable to estimate the amount of unrecognized tax benefits for Great Plains Energy that may be recognized in the next twelve months. Great Plains Energy files a consolidated federal income tax return as well as unitary and combined income tax returns in several state jurisdictions with Kansas and Missouri being the most significant. The Company also files separate company returns in Canada and certain other states. |
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- References No definition available.
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- Definition The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Segments and Related Information |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Segment Reporting [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Segments and Related Information | 22. SEGMENTS AND RELATED INFORMATION Great Plains Energy has one reportable segment based on its method of internal reporting, which segregates reportable segments based on products and services, management responsibility and regulation. The one reportable business segment is electric utility, consisting of KCP&L, GMO's regulated utility operations and GMO Receivables Company. Other includes GMO activity other than its regulated utility operations, GPETHC and unallocated corporate charges. The summary of significant accounting policies applies to the reportable segment. Segment performance is evaluated based on net income. The following tables reflect summarized financial information concerning Great Plains Energy's reportable segment.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Jointly Owned Electric Utility Plants |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Jointly Owned Electric Utility Plants [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Jointly Owned Electric Utility Plants [Text Block] | 23. JOINTLY-OWNED ELECTRIC UTILITY PLANTS Great Plains Energy's and KCP&L's share of jointly-owned electric utility plants at December 31, 2015, are detailed in the following tables.
Each owner must fund its own portion of the plant's operating expenses and capital expenditures. KCP&L's and GMO's share of direct expenses are included in the appropriate operating expense classifications in Great Plains Energy's and KCP&L's financial statements. |
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure on jointly owned electric utility plants. No definition available.
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Quarterly Operating Results (Unaudited) |
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| Quarterly Financial Information Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Quarterly Financial Information [Text Block] | 24. QUARTERLY OPERATING RESULTS (UNAUDITED)
Quarterly data is subject to seasonal fluctuations with peak periods occurring in the summer months. |
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Schedule I Financial Statements of Parent Company |
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| Condensed Financial Information of Parent Company Only Disclosure [Text Block] |
The accompanying Notes to Financial Statements of Parent Company are an integral part of these statements.
The accompanying Notes to Financial Statements of Parent Company are an integral part of these statements.
The accompanying Notes to Financial Statements of Parent Company are an integral part of these statements. The Great Plains Energy Incorporated Notes to Consolidated Financial Statements in Part II, Item 8 should be read in conjunction with the Great Plains Energy Incorporated Parent Company Financial Statements. The Great Plains Energy Incorporated Parent Company Financial Statements have been prepared to present the financial position, results of operations and cash flows of Great Plains Energy on a stand-alone basis as a holding company. Investments in subsidiaries are accounted for using the equity method. |
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- Definition The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Schedule II Valuation and Qualifying Accounts |
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| Valuation and Qualifying Accounts [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule II Valuation and Qualifying Accounts |
(a) Recoveries. (b) Uncollectible accounts charged off. (c) Payment of claims. (d) Reversal of tax valuation allowance.
(a) Recoveries. (b) Uncollectible accounts charged off. (c) Payment of claims. |
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- Definition The entire disclosure for any allowance and reserve accounts (their beginning and ending balances, as well as a reconciliation by type of activity during the period). Alternatively, disclosure of the required information may be within the footnotes to the financial statements or a supplemental schedule to the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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Summary of Significant Accounting Policies (Policies) |
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| Accounting Policies [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Organization [Policy Text Block] | Organization Great Plains Energy, a Missouri corporation incorporated in 2001, is a public utility holding company and does not own or operate any significant assets other than the stock of its subsidiaries. Great Plains Energy's wholly owned direct subsidiaries with significant operations are as follows:
Great Plains Energy also wholly owns GPE Transmission Holding Company, LLC (GPETHC). GPETHC owns 13.5% of Transource Energy, LLC (Transource) with the remaining 86.5% owned by AEP Transmission Holding Company, LLC (AEPTHC), a subsidiary of American Electric Power Company, Inc. GPETHC accounts for its investment in Transource under the equity method. Transource is focused on the development of competitive electric transmission projects. Each of Great Plains Energy's and KCP&L's consolidated financial statements includes the accounts of their subsidiaries. Intercompany transactions have been eliminated. Great Plains Energy's sole reportable business segment is electric utility. See Note 22 for additional information. |
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| Use of Estimates, Policy [Policy Text Block] | Use of Estimates The process of preparing financial statements in conformity with Generally Accepted Accounting Principles (GAAP) requires the use of estimates and assumptions that affect the reported amounts of certain types of assets, liabilities, revenues and expenses. Such estimates primarily relate to unsettled transactions and events as of the date of the financial statements. Accordingly, upon settlement, actual results may differ from estimated amounts. |
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| Cash and Cash Equivalents, Policy [Policy Text Block] | Cash and Cash Equivalents Cash equivalents consist of highly liquid investments with original maturities of three months or less at acquisition. |
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| Funds on Deposit, Policy [Policy Text Block] | Funds on Deposit Funds on deposit consist primarily of cash provided to counterparties in support of margin requirements related to commodity purchases, commodity swaps and futures contracts. Pursuant to individual contract terms with counterparties, deposit amounts required vary with changes in market prices, credit provisions and various other factors. Interest is earned on most funds on deposit. Great Plains Energy also holds funds on deposit from counterparties in the same manner. These funds are included in other current liabilities on the consolidated balance sheets. |
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| Fair Value of Financial Instruments, Policy [Policy Text Block] | Fair Value of Financial Instruments The following methods and assumptions were used to estimate the fair value of each class of financial instrument for which it is practicable to estimate that value. Nuclear decommissioning trust fund - KCP&L's nuclear decommissioning trust fund assets are recorded at fair value based on quoted market prices of the investments held by the fund and/or valuation models. Derivative instruments - The fair value of derivative instruments is estimated using market quotes, over-the-counter forward price and volatility curves and correlation among fuel prices, net of estimated credit risk. Pension plans - For financial reporting purposes, the market value of plan assets is the fair value. For regulatory reporting purposes, a five-year smoothing of assets is used to determine fair value. |
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| Derivatives, Policy [Policy Text Block] | Derivative Instruments The Company records derivative instruments on the balance sheet at fair value in accordance with GAAP. Great Plains Energy and KCP&L enter into derivative contracts to manage exposure to commodity price and interest rate fluctuations. Derivative instruments are used solely for hedging purposes and are not issued or held for speculative reasons. The Company considers various qualitative factors, such as contract and market place attributes, in designating derivative instruments at inception. Great Plains Energy and KCP&L may elect the normal purchases and normal sales (NPNS) exception, which requires the effects of the derivative to be recorded when the underlying contract settles. Great Plains Energy and KCP&L account for derivative instruments that are not designated as NPNS as non-hedging derivatives, which are recorded as assets or liabilities on the consolidated balance sheets at fair value. See Note 18 for additional information regarding derivative financial instruments and hedging activities. Great Plains Energy and KCP&L offset fair value amounts recognized for derivative instruments under master netting arrangements, which include rights to reclaim cash collateral (a receivable), or the obligation to return cash collateral (a payable). |
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| Utility Plant, Policy [Policy Text Block] | Utility Plant Great Plains Energy's and KCP&L's utility plant is stated at historical cost. These costs include taxes, an allowance for the cost of borrowed and equity funds used to finance construction and payroll-related costs, including pensions and other fringe benefits. Replacements, improvements and additions to units of property are capitalized. Repairs of property and replacements of items not considered to be units of property are expensed as incurred (except as discussed under Deferred Refueling Outage Costs). When property units are retired or otherwise disposed, the original cost, net of salvage, is charged to accumulated depreciation. Substantially all of KCP&L's utility plant is pledged as collateral for KCP&L's mortgage bonds under the General Mortgage Indenture and Deed of Trust dated December 1, 1986, as supplemented. Substantially all of GMO's St. Joseph Light & Power division utility plant is pledged as collateral for GMO's mortgage bonds under the General Mortgage Indenture and Deed of Trust dated April 1, 1946, as supplemented. As prescribed by The Federal Energy Regulatory Commission (FERC), Allowance for Funds Used During Construction (AFUDC) is charged to the cost of the plant during construction. AFUDC equity funds are included as a non-cash item in non-operating income and AFUDC borrowed funds are a reduction of interest charges. The rates used to compute gross AFUDC are compounded semi-annually. The rates used to compute gross AFUDC for KCP&L averaged 3.0% in 2015, 5.7% in 2014 and 6.1% in 2013. The rates used to compute gross AFUDC for GMO averaged 4.2% in 2015, 6.1% in 2014 and 2.1% in 2013. Great Plains Energy's and KCP&L's balances of utility plant, at original cost, with a range of estimated useful lives are listed in the following tables.
(a) Includes $136.5 million and $72.4 million at December 31, 2015 and 2014, respectively, of land and other assets that are not depreciated. |
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| Depreciation and Amortization, Policy [Policy Text Block] | Depreciation and Amortization Depreciation and amortization of utility plant other than nuclear fuel is computed using the straight-line method over the estimated lives of depreciable property based on rates approved by state regulatory authorities. Annual depreciation rates average approximately 3%. Nuclear fuel is amortized to fuel expense based on the quantity of heat produced during the generation of electricity. Great Plains Energy's depreciation expense was $299.4 million, $277.9 million and $265.4 million for 2015, 2014 and 2013, respectively. KCP&L's depreciation expense was $208.5 million, $189.7 million and $179.2 million for 2015, 2014 and 2013, respectively. |
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| Nuclear Plant Decommissioning Costs, Policy [Policy Text Block] | Nuclear Plant Decommissioning Costs Nuclear plant decommissioning cost estimates are based on the immediate dismantlement method and include the costs of decontamination, dismantlement and site restoration. Based on these cost estimates, KCP&L contributes to a tax-qualified trust fund to be used to decommission Wolf Creek Generating Station (Wolf Creek). Related liabilities for decommissioning are included on Great Plains Energy's and KCP&L's balance sheets in Asset Retirement Obligations (AROs). As a result of the authorized regulatory treatment and related regulatory accounting, differences between the decommissioning trust fund asset and the related ARO are recorded as a regulatory asset or liability. See Note 7 for discussion of AROs including those associated with nuclear plant decommissioning costs. |
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| Deferred Refueling Outage Costs, Policy [Policy Text Block] | Deferred Refueling Outage Costs KCP&L uses the deferral method to account for operations and maintenance expenses incurred in support of Wolf Creek's scheduled refueling outages and amortizes them evenly (monthly) over the unit's operating cycle, which is approximately 18 months, until the next scheduled outage. Replacement power costs during an outage are expensed as incurred. |
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| Regulatory Matters, Policy [Policy Text Block] | Regulatory Matters KCP&L and GMO defer items on the balance sheet resulting from the effects of the ratemaking process, which would not be recorded if KCP&L and GMO were not regulated. See Note 5 for additional information concerning regulatory matters. |
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| Revenue Recognition, Policy [Policy Text Block] | Revenue Recognition Great Plains Energy and KCP&L recognize revenues on sales of electricity when the service is provided. Revenues recorded include electric services provided but not yet billed by KCP&L and GMO. Unbilled revenues are recorded for kWh usage in the period following the customers' billing cycle to the end of the month. KCP&L's and GMO's estimate is based on net system kWh usage less actual billed kWhs. KCP&L's and GMO's estimated unbilled kWhs are allocated and priced by regulatory jurisdiction across the rate classes based on actual billing rates. KCP&L and GMO collect from customers gross receipts taxes levied by state and local governments. These taxes from KCP&L's Missouri customers are recorded gross in operating revenues and general taxes on Great Plains Energy's and KCP&L's statements of comprehensive income. KCP&L's gross receipts taxes collected from Missouri customers were $62.0 million, $60.4 million and $58.9 million in 2015, 2014 and 2013, respectively. These taxes from KCP&L's Kansas customers and GMO's customers are recorded net in operating revenues on Great Plains Energy's and KCP&L's statements of comprehensive income. Great Plains Energy and KCP&L collect sales taxes from customers and remit to state and local governments. These taxes are presented on a net basis on Great Plains Energy's and KCP&L's statements of comprehensive income. Great Plains Energy and KCP&L record sale and purchase activity on a net basis in wholesale revenue or purchased power when transacting with Regional Transmission Organization (RTO)/Independent System Operator (ISO) markets. |
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| Allowance for Doubtful Accounts, Policy [Policy Text Block] | Allowance for Doubtful Accounts This reserve represents estimated uncollectible accounts receivable and is based on management's judgment considering historical loss experience and the characteristics of existing accounts. Provisions for losses on receivables are expensed to maintain the allowance at a level considered adequate to cover expected losses. Receivables are charged off against the reserve when they are deemed uncollectible. |
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| Property Gains And Losses, Policy [Policy Text Block] | Property Gains and Losses Net gains and losses from the sale of assets and businesses and from asset impairments are recorded in operating expenses. |
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| Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] | Asset Impairments Long-lived assets and finite-lived intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the undiscounted expected future cash flows from an asset to be held and used is less than the carrying value of the asset, an asset impairment must be recognized in the financial statements. The amount of impairment recognized is the excess of the carrying value of the asset over its fair value. Goodwill and indefinite lived intangible assets are tested for impairment annually and when an event occurs indicating the possibility that an impairment exists. The annual test must be performed at the same time each year. If the fair value of a reporting unit is less than its carrying value including goodwill, an impairment charge for goodwill must be recognized in the financial statements. To measure the amount of the impairment loss to recognize, the implied fair value of the reporting unit goodwill is compared with its carrying value. |
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| Income Taxes, Policy [Policy Text Block] | Income Taxes Income taxes are accounted for using the asset/liability approach. Deferred tax assets and liabilities are determined based on the temporary differences between the financial reporting and tax bases of assets and liabilities, applying enacted statutory tax rates in effect for the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion of the deferred tax assets will not be realized. Great Plains Energy and KCP&L recognize tax benefits based on a “more-likely-than-not” recognition threshold. In addition, Great Plains Energy and KCP&L recognize interest accrued related to unrecognized tax benefits in interest expense and penalties in non-operating expenses. Great Plains Energy files a consolidated federal income tax return as well as unitary and combined income tax returns in several state jurisdictions with Kansas and Missouri being the most significant. Income taxes for consolidated or combined subsidiaries are allocated to the subsidiaries based on separate company computations of income or loss. KCP&L's income tax provision includes taxes allocated based on its separate company income or loss. Great Plains Energy and KCP&L have established a net regulatory asset for the additional future revenues to be collected from customers for deferred income taxes. Tax credits are recognized in the year generated except for certain KCP&L and GMO investment tax credits that have been deferred and amortized over the remaining service lives of the related properties. |
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| Environmental Matters, Policy [Policy Text Block] | Environmental Matters Environmental costs are accrued when it is probable a liability has been incurred and the amount of the liability can be reasonably estimated. |
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| Basic and Diluted Earnings per Common Share Calculation [Policy Text Block] | Basic and Diluted Earnings per Common Share Calculation To determine basic earnings per common share (EPS), preferred stock dividend requirements are deducted from net income before dividing by the average number of common shares outstanding. The effect of dilutive securities, calculated using the treasury stock method, assumes the issuance of common shares applicable to performance shares and restricted stock. |
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| New Accounting Pronouncements, Policy [Policy Text Block] | ASU No. 2015-03 - Simplifying the Presentation of Debt Issuance Costs In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-03, Simplifying the Presentation of Debt Issuance Costs, which requires that debt issuance costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The new guidance is to be applied retrospectively and is effective for interim and annual periods beginning after December 15, 2015, with early adoption permitted. The Companies elected to early adopt at December 31, 2015, and accordingly have retrospectively adjusted prior periods. The following table reflects the change on the line items of Great Plains Energy's and KCP&L's consolidated balance sheets at December 31, 2014.
ASU No. 2015-07 - Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) In May 2015, the FASB issued ASU No. 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). This guidance removes the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. The new guidance is effective for interim and annual periods beginning after December 15, 2015, with early adoption permitted. The Companies elected to early adopt at December 31, 2015, and accordingly have retrospectively adjusted prior periods. ASU No. 2015-17 - Balance Sheet Classification of Deferred Taxes In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes, which simplifies the presentation of deferred taxes by requiring deferred tax assets and liabilities be classified as noncurrent on the balance sheet. The new guidance is effective for interim and annual periods beginning after December 15, 2016, with early adoption permitted. The Companies elected to early adopt this guidance, prospectively, at December 31, 2015. Prior periods were not retrospectively adjusted. ASU No. 2014-09 - Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in GAAP when it becomes effective. In August 2015, the FASB issued ASU No. 2015-14, deferring the effective date of ASU No. 2014-09 one year, from January 1, 2017, to January 1, 2018. The Companies plan to adopt ASU No. 2014-09 on January 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition method. The Companies are evaluating the effect that ASU No. 2014-09 will have on their consolidated financial statements and related disclosures and have not yet selected a transition method nor have they determined the effect of the standard on their ongoing financial reporting. |
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- Definition Disclosure of accounting policy for gains and losses on sales of property and from asset impairments. No definition available.
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- Definition Disclosure of accounting policy for determining amounts to accrue and charge against earnings so as to satisfy legal obligations associated with the retirement (through sale, abandonment, recycling, or disposal in some other manner) of a tangible long-lived asset that result from the acquisition, construction, or development and (or) the normal operation of a long-lived asset. This accounting policy disclosure excludes obligations arising 1) in connection with leased property, whether imposed by a lease agreement or by a party other than the lessor, that meet the definition of either minimum lease payments or contingent rentals; 2) solely from a plan to sell or otherwise dispose of a long-lived asset and 3) from certain environmental remediation liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Entity's cash and cash equivalents accounting policy with respect to restricted balances. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for its derivative instruments and hedging activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for determining the fair value of financial instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for recognizing and measuring the impairment of long-lived assets. An entity also may disclose its accounting policy for long-lived assets to be sold. This policy excludes goodwill and intangible assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy pertaining to new accounting pronouncements that may impact the entity's financial reporting. Includes, but is not limited to, quantification of the expected or actual impact. No definition available.
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- Definition Disclosure of accounting policy for planned major maintenance activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, basis of assets, depreciation and depletion methods used, including composite deprecation, estimated useful lives, capitalization policy, accounting treatment for costs incurred for repairs and maintenance, capitalized interest and the method it is calculated, disposals and impairments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for public utilities. Examples include a discussion about the scope criteria and appropriateness for and extent of the application of generally accepted accounting principles related to accounting for the effects of certain types of regulation (may include identification of specific business units). Other examples of the disclosures may include: descriptions of the form and economic effects of regulation (for example, but not limited to, recording of regulatory assets and liabilities to the rate setting process); statement about periodic assessments of periodic assessments of generally accepted accounting principles related to accounting for the effects of certain types of regulation; information regarding amortization of and return on regulatory assets and liabilities, including the remaining amounts and recovery or settlement periods; accounting for changes to recovery estimates; AFUDC, plant abandonment's and plant disallowances. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for determining the allowance for doubtful accounts for trade and other accounts receivable balances, and when impairments, charge-offs or recoveries are recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for systematically allocating capitalized costs to periods that benefit from the use thereof. Includes, but is not limited to, methods used, such as composite depreciation, descriptions of regulatory treatment for estimated removal and disposal costs, and description of amortization of plant-related regulatory assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for liabilities for remediation of environmental matters. The accounting policy may specify the conditions under which rate actions of a regulator provide reasonable assurance of the existence of an asset pertaining thereto. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Summary of Significant Accounting Policies (Tables) |
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| Accounting Policies [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Public Utility Property, Plant, and Equipment [Table Text Block] |
(a) Includes $136.5 million and $72.4 million at December 31, 2015 and 2014, respectively, of land and other assets that are not depreciated. |
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| Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] | The following table reconciles Great Plains Energy's basic and diluted EPS.
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| Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] | Anti-dilutive shares excluded from the computation of diluted EPS are detailed in the following table.
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| New Accounting Pronouncement, Early Adoption [Table Text Block] |
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- Definition Tabular disclosure of financial statement line items and the effect of the guidance on the financial statement line items if the entity elects early adoption of accounting guidance. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented, by antidilutive securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of an entity's basic and diluted earnings per share calculations, including a reconciliation of numerators and denominators of the basic and diluted per-share computations for income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of public utility physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, deprecation expense and method used, including composite depreciation, and accumulated deprecation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Supplemental Cash Flow Information (Tables) |
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| Supplemental Cash Flow Elements [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] |
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- Definition Tabular disclosure of supplemental cash flow information for the periods presented. No definition available.
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- References No definition available.
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Receivables (Tables) |
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| Receivables [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of receivables [Table Text Block] | Great Plains Energy's and KCP&L's receivables are detailed in the following table.
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- References No definition available.
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- Definition Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Nuclear Plant (Tables) |
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| Nuclear Plant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Changes in nuclear decommissioning trust fund | The following table summarizes the change in Great Plains Energy's and KCP&L's nuclear decommissioning trust fund.
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| Detail of assets held in nuclear decommissioning trust fund | The nuclear decommissioning trust is reported at fair value on the balance sheets and is invested in assets as detailed in the following table.
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| Gains and losses from the sale of securities by the nuclear decommissioning trust fund | The following table summarizes the realized gains and losses from the sale of securities in the nuclear decommissioning trust fund.
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| Nuclear plant decommissioning costs [Table Text Block] |
(a) Total future cost over an eight year decommissioning period (b) The 6.43% and 5.89% rate of return for KCC and MPSC, respectively, is through 2025. The rates then systematically decrease through 2053 to 0.72% and 2.22% for KCC and MPSC, respectively, based on the assumption that the fund's investment mix will become increasingly conservative as the decommissioning period approaches. |
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- Definition A tabular disclosure that summarizes the change in nuclear decommissioning trust fund during the period. No definition available.
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- Definition This item represents the entire disclosure related to nuclear decommissioning trust fund which consist of all investments in certain debt and equity securities (and other assets). The nuclear decommission fund is maintained to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. No definition available.
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- Definition This item represents the entire disclosure related to realized gain or loss on sale of securities related to nuclear decommissioning trust fund. No definition available.
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- Definition A tabular disclosure of current and future decommissioning costs related to nuclear plants. No definition available.
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Regulatory Matters (Tables) |
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| Regulated Operations [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule Of Regulatory Assets And Liabilities [Table Text Block] | Great Plains Energy's and KCP&L's regulatory assets and liabilities are detailed in the following table.
(a) Amortized over the life of the related new debt issuances or the remaining lives of the old debt issuances if no new debt was issued. (b) Represents unrecognized gains and losses, prior service and transition costs that will be recognized in future net periodic pension and post-retirement costs, pension settlements amortized over various periods and financial and regulatory accounting method differences that will be eliminated over the life of the pension plans. Of these amounts, $343.7 million and $54.5 million for KCP&L and GMO, respectively, are not included in rate base and are amortized over various periods. (c) $8.3 million not included in rate base and amortized over various periods. (d) $7.4 million not included in rate base and amortized over various periods. (e) Not included in rate base and amortized over various periods. (f) Represents fair value of derivative instruments for commodity contracts. Settlements of the contracts are recognized in the income statement and included in fuel recovery mechanisms. (g) Included in rate base and amortized through 2038. (h) Included in rate base and amortized through 2058. (i) Included in rate base and amortized through 2040. (j) Estimated cumulative net provision for future removal costs. |
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- Definition Tabular disclosure of assets and liabilities created when regulatory agencies permit public utilities to defer certain costs included in rate-setting to the balance sheet or when the rate actions of a regulator impose a liability on a regulated enterprise resulting in a regulatory liability. No definition available.
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Goodwill and Intangible Assets (Tables) |
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| Finite-Lived Intangible Assets [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Finite-Lived Intangible Assets [Table Text Block] | Great Plains Energy's and KCP&L's intangible assets are included in electric utility plant on the consolidated balance sheets and are detailed in the following table.
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| Amortization Expense Related to Intangible Assets [Table Text Block] | Great Plains Energy's and KCP&L's amortization expense related to intangible assets is detailed in the following table.
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| Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] | The following table provides the estimated amortization expense related to Great Plains Energy's and KCP&L's intangible assets for 2016 through 2020 for the intangible assets included in the consolidated balance sheets at December 31, 2015.
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| X | ||||||||||
- Definition Tabular disclosure of amortization expense of assets, excluding financial assets, that lack physical substance, having a limited useful life. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite life, by either major class or business segment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Asset Retirement Obligations (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Asset Retirement Obligation Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Change in Asset Retirement Obligation [Table Text Block] | The following table summarizes the change in Great Plains Energy's and KCP&L's AROs.
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- References No definition available.
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- Definition Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Pension Plans and Other Employee Benefits (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Net Benefit Costs [Table Text Block] |
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| Schedule of Net Funded Status [Table Text Block] |
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| Schedule Of Periodic Benefit Obligation And Accumulated Benefit Obligation And Fair Value Of Plan Assets By Funded And Under Funded Plans [Table Text Block] |
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| Schedule of Assumptions Used [Table Text Block] |
*after tax |
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| Schedule of Expected Benefit Payments [Table Text Block] |
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| Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] |
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| Pension Plans, Defined Benefit [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Allocation of Plan Assets [Table Text Block] |
(a) At December 31, 2015 and 2014, this category is comprised of $121.6 million and $78.1 million, respectively, of traded mutual funds valued at daily listed prices and $73.9 million and $125.5 million, respectively, of traded common stocks and exchange traded funds. At December 31, 2015 and 2014, this category also includes $30.5 million and $31.6 million, respectively, of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (b) At December 31, 2015 and 2014, this category is comprised of $34.2 million and $38.6 million, respectively, of traded mutual funds valued at daily listed prices and $75.5 million and $70.1 million, respectively, of traded American depository receipts, global depository receipts and ordinary shares. At December 31, 2015 and 2014, this category also includes $37.7 million and $38.6 million, respectively, of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (c) At December 31, 2015 and 2014, this category is comprised of $12.2 million and $7.7 million, respectively, of traded real estate investment trusts. At December 31, 2015 and 2014, this category also includes $33.7 million and $31.2 million, respectively, of institutional common/collective trust funds and a limited partnership valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (d) Consists of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (e) At December 31, 2015 and 2014, this category is comprised of $20.0 million and $22.3 million, respectively, of traded mutual funds valued at daily listed prices. At December 31, 2015 and 2014, this category also includes $40.4 million and $43.8 million, respectively, of institutional common/collective trust funds valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (f) At December 31, 2015 and 2014, this category is comprised of $103.0 million and $100.3 million, respectively, of corporate bonds, $2.9 million and $4.0 million, respectively, of collateralized mortgage obligations and $2.9 million and $4.7 million, respectively, of other asset-backed securities. (g) Consists of closely-held limited partnerships valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. |
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| Other Postretirement Benefit Plans, Defined Benefit [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Allocation of Plan Assets [Table Text Block] |
(a) At December 31, 2015 and 2014 this category is comprised of $0.1 million and $0.2 million, respectively, of traded mutual funds valued at daily listed prices. At December 31, 2015 and 2014 this category also includes $68.8 million and $72.8 million, respectively, of an institutional common/collective trust fund valued at NAV per share (or its equivalent) and is not categorized in the fair value hierarchy. (b) At December 31, 2015 and 2014, this category is comprised of $12.6 million and $10.3 million, respectively, of corporate bonds, $0.6 million and $0.8 million, respectively, of collateralized mortgage obligations and $2.4 million and $1.9 million, respectively, of other asset-backed securities. |
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- Definition Tabular disclosure of periodic benefit obligation and accumulated benefit obligation and the fair value of plan assets by funded and under funded plans. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation and net benefit cost, including assumed discount rates, rate increase in compensation increase, and expected long-term rates of return on plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the effect of a one-percentage-point increase and the effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs and the accumulated postretirement benefit obligation for health care benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of net funded status of pension plans and/or other employee benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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Equity Compensation (Tables) |
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| Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Performance share activity |
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| Restricted stock activity |
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| Director Deferred Share Units |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Tabular disclosure of the amount of total share-based compensation cost, including the amounts attributable to each share-based compensation plan and any related tax benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of an equity-based arrangement (such as stock or unit options and stock or unit awards) with an individual employee, which is generally an employment contract between the entity and a selected officer or key employee containing a promise by the employer to pay certain equity-based awards at future dates, sometimes including a period after retirement, upon compliance with stipulated requirements. This type of arrangement is distinguished from broader based employee benefit plans as it is usually tailored to the employee. Disclosure also typically includes the amount of related compensation expense recognized during the reporting period, the number of shares or units issued during the period under such arrangements, and the carrying amount as of the balance sheet date of the related liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the changes in outstanding nonvested performance-based units. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the changes in outstanding nonvested restricted stock units. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Long-Term Debt (Tables) |
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| Debt Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Debt [Table Text Block] | Great Plains Energy's and KCP&L's long-term debt is detailed in the following table.
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| Amortization Of Debt Expense [Table Text Block] | Great Plains Energy's and KCP&L's amortization of debt expense is detailed in the following table.
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| Schedule of Maturities of Long-term Debt [Table Text Block] | Great Plains Energy's and KCP&L's long-term debt maturities for the next five years are detailed in the following table.
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| X | ||||||||||
- Definition Tabular disclosure of the component of interest expense representing noncash expenses charged against earnings in the period to amortize debt discount and premium associated with the related debt instruments. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of information pertaining to short-term and long-debt instruments or arrangements, including but not limited to identification of terms, features, collateral requirements and other information necessary to a fair presentation. No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Commitments and Contingencies (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Commitments and Contingencies Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Rent Expense [Table Text Block] |
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| Unrecorded Unconditional Purchase Obligations And Lease Commitments [Table Text Block] |
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| Schedule Of Environmental Capital Expenditures [Table Text Block] |
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| X | ||||||||||
- Definition Tabular disclosure of environmental expenditures (exclusive of Allowance for Funds Used During Construction and property taxes) over the next five years to comply with environmental regulations. No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of unconditional purchase obligations and lease commitments that are not recognized as liabilities on the balance sheet. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of rental expense from operating leases for each period for which an income statement is presented with separate amounts for minimum rentals, contingent rentals, and sublease rentals. Rental payments under leases with terms of a month or less that were not renewed need not be included. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Related Party Transactions and Relationships (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Related Party Transactions [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of related party receivables and payables [Table Text Block] | The following table summarizes KCP&L's related party net receivables.
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| X | ||||||||||
- Definition Tabular disclosure of related party receivables and payables. No definition available.
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| X | ||||||||||
- References No definition available.
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Derivative Instruments (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Derivative Instruments and Hedging Activities Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Values of open positions for derivative instruments [Table Text Block] | The gross notional contract amount and recorded fair values of open positions for derivative instruments are summarized in the following table. The fair values of these derivatives are recorded on the consolidated balance sheets. The fair values below are gross values before netting agreements and netting of cash collateral.
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| Fair value of open derivative positions, gross values before netting agreements and netting of cash collatral [Table Text Block] | The fair values of Great Plains Energy's and KCP&L's open derivative positions and balance sheet classification are summarized in the following tables. The fair values below are gross values before netting agreements and netting of cash collateral.
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| Offsetting Derivative Assets and Liabilities [Table Text Block] | The following tables provide information regarding Great Plains Energy's and KCP&L's offsetting of derivative assets and liabilities.
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| Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] | The following tables summarize the amounts of gain (loss) recognized for the change in fair value of commodity contract derivatives not designated as hedging instruments for Great Plains Energy and KCP&L.
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- Definition [Table Text Block] for Tabular disclosure of derivative assets and liabilities that are subject to offsetting, including master netting arrangements. [Table] No definition available.
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- References No definition available.
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- Definition Tabular disclosure of the location and fair value amounts of derivative instruments (and nonderivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure for other derivative instruments not designated as hedging instruments of (a) the location and amount of gains and losses reported in the statement of financial performance and (b) the location and fair value amounts of the instruments reported in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Fair Value Disclosures [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Fair value of assets and liabilities | The following tables include Great Plains Energy's and KCP&L's balances of financial assets and liabilities measured at fair value on a recurring basis. The fair values below are gross values before netting arrangements and netting of cash collateral.
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| Unobservable inputs reconciliation | The following tables reconcile the beginning and ending balances for all Level 3 assets and liabilities measured at fair value on a recurring basis.
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- References No definition available.
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- Definition Tabular disclosure of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) using recurring unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Accumulated Other Comprehensive Income (Loss) (Tables) |
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| Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] | The following tables reflect the change in the balances of each component of accumulated other comprehensive loss for Great Plains Energy and KCP&L.
(a) Net of tax
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| Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] | The following tables reflect the effect on certain line items of net income from amounts reclassified out of each component of accumulated other comprehensive loss for Great Plains Energy and KCP&L.
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- Definition Tabular disclosure of information about items reclassified out of accumulated other comprehensive income (loss). No definition available.
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- Definition Tabular disclosure of the components of accumulated other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Taxes (Tables) |
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| Income Tax Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] |
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| Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] |
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| Schedule of Deferred Tax Assets and Liabilities [Table Text Block] |
(a) Reflects adoption of ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes. See Note 1 to the consolidated financial statements under the heading New Accounting Standards for additional information.
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| Summary of Income Tax Contingencies [Table Text Block] |
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- References No definition available.
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- Definition Tabular disclosure of the components of income tax expense attributable to continuing operations for each year presented including, but not limited to: current tax expense (benefit), deferred tax expense (benefit), investment tax credits, government grants, the benefits of operating loss carryforwards, tax expense that results from allocating certain tax benefits either directly to contributed capital or to reduce goodwill or other noncurrent intangible assets of an acquired entity, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity, and adjustments of the beginning-of-the-year balances of a valuation allowance because of a change in circumstances that causes a change in judgment about the realizability of the related deferred tax asset in future years. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the components of net deferred tax asset or liability recognized in an entity's statement of financial position, including the following: the total of all deferred tax liabilities, the total of all deferred tax assets, the total valuation allowance recognized for deferred tax assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities (i.e., uncertain tax positions) and other types of income tax contingencies, including: (1) the policy on classification of interest and penalties; (2) a tabular reconciliation of the total amounts of unrecognized tax benefits at the beginning and end of the period; the total amount(s) of: (3) unrecognized tax benefits that, if recognized, would affect the effective tax rate, and (4) interest and penalties recognized in each of the income statement and balance sheet; (5) for positions for which it is reasonably possible that the total amounts unrecognized will significantly change within 12 months of the reporting date the: (i) nature of the uncertainty, (ii) nature of the event that could occur that would cause the change, and (iii) an estimate of the range of the reasonably possible change or a statement that an estimate of the range cannot be made; and (6) a description of tax years that remain subject to examination by major tax jurisdictions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Segments and Related Information (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Segment Reporting [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Segment Financial Information [Table Text Block] |
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| X | ||||||||||
- Definition Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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Jointly Owned Electric Utility Plants (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Jointly Owned Electric Utility Plants [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Jointly Owned Utility Plants [Table Text Block] | Great Plains Energy's and KCP&L's share of jointly-owned electric utility plants at December 31, 2015, are detailed in the following tables.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of proportionate interests in jointly owned utility plants. Includes the amount of plants in service, the accumulated provision for depreciation (if available), the amount of plants under construction, and the proportionate share. The amounts presented may be further subdivided to show amounts applicable to plant subcategories (for example, production, transmission, distribution). Includes statements that the amounts represent the utility's share in each joint plant and that it must provide its own financing. Information concerning two or more generating plants on the same site may be combined. States that the utility's share of direct expenses of the joint plants is included in the corresponding operating expenses on its income statement (for example, fuel, maintenance of plant, other operating expense). If the share of direct expenses is charged to purchased power, then disclose the amount so charged and the proportionate amounts charged to specific operating expenses on the records maintained for the joint plants. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Quarterly Operating Results (Unaudited) (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2015 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Quarterly Financial Information Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Quarterly Financial Information [Table Text Block] |
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of the quarterly financial data in the annual financial statements. The disclosure includes financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income (loss) before extraordinary items and cumulative effect of a change in accounting principle and earnings per share data. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Summary of Significant Accounting Policies Equity Method Investment (Details) - Transource Energy, LLC [Member] |
12 Months Ended |
|---|---|
Dec. 31, 2015 | |
| Schedule of Equity Method Investments [Line Items] | |
| Equity Method Investment, Description of Principal Activities | Transource is focused on the development of competitive electric transmission projects. |
| GPE Transmission Holding Company, LLC [Member] | |
| Schedule of Equity Method Investments [Line Items] | |
| Equity Method Investment, Ownership Percentage | 13.50% |
| AEP Transmission Holding Company, LLC [Member] | |
| Schedule of Equity Method Investments [Line Items] | |
| Ownership Percentage of Majority Owner | 86.50% |
| X | ||||||||||
- Definition A description of the principal activities of an investee accounted for under the equity method. No definition available.
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| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. No definition available.
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies Summary of Significant Accounting Policies Utility Plant (Details) - USD ($) $ in Millions |
12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service | 3.00% | |||||||
| Depreciation | $ 299.4 | $ 277.9 | $ 265.4 | |||||
| Depreciation and amortization | 330.4 | 306.0 | 289.7 | |||||
| Utility Plant, at original cost | ||||||||
| Public Utilities, Property, Plant and Equipment, Generation or Processing | 7,923.8 | 7,169.6 | ||||||
| Public Utilities, Property, Plant and Equipment, Transmission | 848.8 | 821.9 | ||||||
| Public Utilities, Property, Plant and Equipment, Distribution | 3,498.6 | 3,311.6 | ||||||
| Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment | 918.7 | 825.6 | ||||||
| Public Utilities, Property, Plant and Equipment, Plant in Service | [1] | $ 13,189.9 | 12,128.7 | |||||
| Minimum [Member] | ||||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Public Utilities, Property, Plant and Equipment, Generation, Useful Life | 20 years | |||||||
| Public Utilities, Property, Plant and Equipment, Transmission, Useful Life | 15 years | |||||||
| Public Utilities, Property, Plant and Equipment, Distribution, Useful Life | 8 years | |||||||
| Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life | 5 years | |||||||
| Maximum [Member] | ||||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Public Utilities, Property, Plant and Equipment, Generation, Useful Life | 60 years | |||||||
| Public Utilities, Property, Plant and Equipment, Transmission, Useful Life | 70 years | |||||||
| Public Utilities, Property, Plant and Equipment, Distribution, Useful Life | 66 years | |||||||
| Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life | 50 years | |||||||
| Land and other assets not depreciated [Member] | ||||||||
| Utility Plant, at original cost | ||||||||
| Public Utilities, Property, Plant and Equipment, Plant in Service | $ 214.0 | 127.9 | ||||||
| Kansas City Power and Light Company [Member] | ||||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Depreciation | 208.5 | 189.7 | 179.2 | |||||
| Depreciation and amortization | $ 235.7 | $ 213.9 | $ 198.3 | |||||
| Public Utilities, Allowance for Funds Used During Construction, Rate | 3.00% | 5.70% | 6.10% | |||||
| Utility Plant, at original cost | ||||||||
| Public Utilities, Property, Plant and Equipment, Generation or Processing | $ 6,222.5 | $ 5,554.3 | ||||||
| Public Utilities, Property, Plant and Equipment, Transmission | 465.3 | 448.9 | ||||||
| Public Utilities, Property, Plant and Equipment, Distribution | 2,215.2 | 2,089.0 | ||||||
| Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment | 737.4 | 645.1 | ||||||
| Public Utilities, Property, Plant and Equipment, Plant in Service | [2] | $ 9,640.4 | 8,737.3 | |||||
| Kansas City Power and Light Company [Member] | Minimum [Member] | ||||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Public Utilities, Property, Plant and Equipment, Generation, Useful Life | 20 years | |||||||
| Public Utilities, Property, Plant and Equipment, Transmission, Useful Life | 15 years | |||||||
| Public Utilities, Property, Plant and Equipment, Distribution, Useful Life | 8 years | |||||||
| Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life | 5 years | |||||||
| Kansas City Power and Light Company [Member] | Maximum [Member] | ||||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Public Utilities, Property, Plant and Equipment, Generation, Useful Life | 60 years | |||||||
| Public Utilities, Property, Plant and Equipment, Transmission, Useful Life | 70 years | |||||||
| Public Utilities, Property, Plant and Equipment, Distribution, Useful Life | 55 years | |||||||
| Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life | 50 years | |||||||
| Kansas City Power and Light Company [Member] | Land and other assets not depreciated [Member] | ||||||||
| Utility Plant, at original cost | ||||||||
| Public Utilities, Property, Plant and Equipment, Plant in Service | $ 136.5 | $ 72.4 | ||||||
| KCPL Greater Missouri Operations [Member] | ||||||||
| Public Utility, Property, Plant and Equipment [Line Items] | ||||||||
| Public Utilities, Allowance for Funds Used During Construction, Rate | 4.20% | 6.10% | 2.10% | |||||
| ||||||||
| X | ||||||||||
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Effective rate, including composite rate, of cost of financing additions to qualifying regulated assets, commonly called allowance for funds used during construction. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Composite depreciation rate for public utility plants in service. No definition available.
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| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to utility distribution. No definition available.
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| X | ||||||||||
- Definition Useful life of utility distribution assets owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to generation or processing owned by public utility. No definition available.
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| X | ||||||||||
- Definition Useful life of utility generation assets owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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| X | ||||||||||
- Definition Period end book value of other property, plant and equipment (PPE) owned (but not classified elsewhere) by the public utility. No definition available.
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| X | ||||||||||
- Definition Useful life of other property, plant and equipment (PPE) owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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| X | ||||||||||
- Definition Period end amount of total gross PPE. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to utility transmission owned by public utility. No definition available.
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| X | ||||||||||
- Definition Useful life of utility transmission equipment owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies Summary of Significant Accounting Policies Revenue Recognition (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Kansas City Power and Light Company [Member] | MISSOURI | |||
| Excise and Sales Taxes | $ 62.0 | $ 60.4 | $ 58.9 |
| X | ||||||||||
- Definition The amount of excise and sales taxes included in sales and revenues, which are then deducted as a cost of sales. Includes excise taxes, which are applied to specific types of transactions or items (such as gasoline or alcohol); and sales, use and value added taxes, which are applied to a broad class of revenue-producing transactions involving a wide range of goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income [Abstract] | |||||||||||
| Net income (loss) | $ 213.0 | $ 242.8 | $ 250.2 | ||||||||
| Less: preferred stock dividend requirements | 1.6 | 1.6 | 1.6 | ||||||||
| Earnings (loss) available for common shareholders | $ 211.4 | $ 241.2 | $ 248.6 | ||||||||
| Common Shares Outstanding [Abstract] | |||||||||||
| Average number of common shares outstanding (in shares) | 154.2 | 153.9 | 153.5 | ||||||||
| Add: effect of dilutive securities (in shares) | 0.6 | 0.2 | 0.2 | ||||||||
| Diluted average number of common shares outstanding (in shares) | 154.8 | 154.1 | 153.7 | ||||||||
| Earnings Per Share [Abstract] | |||||||||||
| Earnings Per Share, Basic | $ 0.12 | $ 0.96 | $ 0.34 | $ 0.15 | |||||||
| Earnings Per Share, Diluted | $ 0.12 | $ 0.95 | $ 0.34 | $ 0.15 | |||||||
| Earnings Per Share, Basic and Diluted | $ 0.15 | $ 0.82 | $ 0.28 | $ 0.12 | $ 1.37 | $ 1.57 | $ 1.62 | ||||
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. No definition available.
|
| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders. No definition available.
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| X | ||||||||||
- Definition The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
Summary of Significant Accounting Policies Antidilutive Securities (Details) - shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Performance Shares [Member] | |||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 0 | 482,987 | 548,242 |
| Restricted Stock [Member] | |||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 900 | 3,287 | 2,228 |
| X | ||||||||||
- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies Subsequent Events (Details) - Subsequent Event [Member] |
1 Months Ended |
|---|---|
|
Feb. 29, 2016
$ / shares
| |
| Common Stock [Member] | |
| Dividends Declared [Abstract] | |
| Dividends Payable, Date Declared, Month and Year | 2016-02 |
| Dividends Payable, Amount Per Share | $ 0.2625 |
| Dividends Payable, Date to be Paid | Mar. 21, 2016 |
| Dividends Payable, Date of Record | Feb. 29, 2016 |
| Preferred Stock [Member] | |
| Dividends Declared [Abstract] | |
| Dividends Payable, Date Declared, Month and Year | 2016-02 |
| Dividends Payable, Date to be Paid | Jun. 01, 2016 |
| Dividends Payable, Date of Record | May 10, 2016 |
| X | ||||||||||
- Definition Date the declared dividend will be paid, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The per share amount of a dividend declared, but not paid, as of the financial reporting date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The month and year (YYYY-MM) that the dividend to be paid was declared. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format. No definition available.
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| X | ||||||||||
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Summary of Significant Accounting Policies, Adoption of New Accounting Standards (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|||
|---|---|---|---|---|---|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | $ 63.2 | $ 52.3 | |||
| Long-term debt | [1] | 3,745.1 | 3,465.7 | ||
| Adjustments for New Accounting Principle, Early Adoption [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | 52.3 | ||||
| Long-term debt | 3,465.7 | ||||
| Adjustments for New Accounting Principle, Early Adoption [Member] | Scenario, Previously Reported [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | 74.6 | ||||
| Long-term debt | 3,488.0 | ||||
| Adjustments for New Accounting Principle, Early Adoption [Member] | Restatement Adjustment [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | (22.3) | ||||
| Long-term debt | (22.3) | ||||
| Kansas City Power and Light Company [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | 17.6 | 13.8 | |||
| Long-term debt | [1] | $ 2,563.1 | 2,282.8 | ||
| Kansas City Power and Light Company [Member] | Adjustments for New Accounting Principle, Early Adoption [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | 13.8 | ||||
| Long-term debt | 2,282.8 | ||||
| Kansas City Power and Light Company [Member] | Adjustments for New Accounting Principle, Early Adoption [Member] | Scenario, Previously Reported [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | 29.5 | ||||
| Long-term debt | 2,298.5 | ||||
| Kansas City Power and Light Company [Member] | Adjustments for New Accounting Principle, Early Adoption [Member] | Restatement Adjustment [Member] | |||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||||
| Other Investments and Other Assets | (15.7) | ||||
| Long-term debt | $ (15.7) | ||||
| |||||
| X | ||||||||||
- Definition Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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| X | ||||||||||
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Supplemental Cash Flow Information (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Cash flows affected by changes in: | |||
| Receivables | $ 12.5 | $ 3.0 | $ (7.1) |
| Accounts receivable pledged as collateral | (4.0) | 4.0 | (1.0) |
| Fuel inventories | (28.3) | (13.7) | 18.7 |
| Materials and supplies | (3.0) | (0.4) | (1.0) |
| Accounts payable | (11.4) | 15.2 | 26.4 |
| Accrued taxes | 1.1 | 8.3 | 2.2 |
| Accrued interest | 3.4 | (4.1) | 3.9 |
| Deferred refueling outage costs | (6.7) | 17.0 | (17.6) |
| Pension and post-retirement benefit obligations | 18.5 | 25.5 | 31.3 |
| Allowance for equity funds used during construction | (4.8) | (18.0) | (14.1) |
| Fuel recovery mechanism | 47.5 | (28.5) | (1.3) |
| Solar rebates paid | (9.0) | (43.2) | (32.5) |
| Other operating activities | (2.9) | (12.3) | 16.2 |
| Total other operating activities | 12.9 | (47.2) | 24.1 |
| Cash paid during the period: | |||
| Interest Paid, Net | 182.2 | 174.8 | 170.8 |
| Income Taxes Paid | 0.1 | 0.0 | 0.0 |
| Non-cash investing activities: | |||
| Liabilities accrued for capital expenditures | 35.7 | 57.4 | 48.1 |
| Kansas City Power and Light Company [Member] | |||
| Cash flows affected by changes in: | |||
| Receivables | 2.6 | (18.1) | (12.6) |
| Fuel inventories | (24.7) | (8.5) | 13.3 |
| Materials and supplies | (4.5) | (1.1) | 1.1 |
| Accounts payable | (18.0) | 20.4 | 7.3 |
| Accrued taxes | (19.0) | (42.5) | (3.7) |
| Accrued interest | 3.4 | (0.1) | 1.4 |
| Deferred refueling outage costs | (6.7) | 17.0 | (17.6) |
| Pension and post-retirement benefit obligations | 18.4 | 26.9 | 35.7 |
| Allowance for equity funds used during construction | (3.8) | (16.0) | (14.1) |
| Fuel recovery mechanism | 3.5 | (2.2) | (1.8) |
| Solar rebates paid | (7.2) | (17.3) | (8.2) |
| Other operating activities | (5.5) | (23.2) | (10.0) |
| Total other operating activities | (61.5) | (64.7) | (9.2) |
| Cash paid during the period: | |||
| Interest Paid, Net | 120.2 | 112.1 | 111.7 |
| Income Taxes Paid | 0.0 | 30.2 | 4.6 |
| Non-cash investing activities: | |||
| Liabilities accrued for capital expenditures | $ 23.9 | $ 48.8 | $ 40.5 |
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the amount due within one year (or one business cycle) from customers for the credit sale of goods and services where those amounts have been pledged as collateral. No definition available.
|
| X | ||||||||||
- Definition The increase (decrease) in deferred refueling outage costs. No definition available.
|
| X | ||||||||||
- Definition The amount of cash paid to customers during the current period for solar rebates. No definition available.
|
| X | ||||||||||
- Definition Total increase (decrease) in operating capital plus other cash or noncash adjustments to reconcile net income to cash provided by (used in) operating activities. No definition available.
|
| X | ||||||||||
- Definition Future cash outflow to pay for construction in progress expenditures that have occurred. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the aggregate amount of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period of all taxes owed but not paid, including income, property and other taxes. No definition available.
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the capitalized cost of equity (based on assumed rate of return) and / or borrowed funds (based on interest rate) used to finance construction of regulated assets, which is expected to be recovered through rate adjustments. As a result of this capitalization, net income is increased. This element pertains to certain regulated industries, such as public utilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the value of fuel held in inventory. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the value of the asset or liability created by an over or under recovery. An over under-recovery means that the basic energy price based on the daily product price and exchange rate is less (over) or more (under) than the basic energy price used in the calculation of the monthly retail energy product. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the amount due to fund pension and non-pension benefits to employees, retired and disabled former employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the value of raw materials, packaging materials and supplies held in inventory. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of cash paid for interest during the period net of cash paid for interest that is capitalized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Other cash or noncash adjustments to reconcile net income to cash provided by (used in) operating activities that are not separately disclosed in the statement of cash flows (for example, cash received or cash paid during the current period for miscellaneous operating activities, net change during the reporting period in other assets or other liabilities). No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Details
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Receivables Accounts, Notes, and Financing (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Other Receivables, Gross, Current | $ 76.5 | $ 86.7 |
| Receivables, net | 147.7 | 160.3 |
| Kansas City Power and Light Company [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Other Receivables, Gross, Current | 69.4 | 79.8 |
| Receivables, net | 129.2 | 128.9 |
| Trade Accounts Receivable [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Allowance for doubtful accounts | (3.8) | (2.8) |
| Trade Accounts Receivable [Member] | Kansas City Power and Light Company [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Allowance for doubtful accounts | (1.8) | (1.2) |
| Trade Accounts Receivable [Member] | Billed Revenues [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Accounts Receivable, Gross, Current | 3.4 | 1.1 |
| Trade Accounts Receivable [Member] | Billed Revenues [Member] | Kansas City Power and Light Company [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Accounts Receivable, Gross, Current | 2.8 | 0.6 |
| Trade Accounts Receivable [Member] | Unbilled Revenues [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Accounts Receivable, Gross, Current | 71.6 | 75.3 |
| Trade Accounts Receivable [Member] | Unbilled Revenues [Member] | Kansas City Power and Light Company [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Accounts Receivable, Gross, Current | $ 58.8 | $ 49.7 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold in the normal course of business. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amounts of other receivables due within one year of the balance sheet date (or one operating cycle, if longer) from third parties or arising from transactions not separately disclosed. No definition available.
|
| X | ||||||||||
- Definition The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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| X | ||||||||||
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| X | ||||||||||
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Receivables Narrative (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Accounts receivable pledged as collateral | $ 175.0 | $ 171.0 |
| Collateralized note payable | 175.0 | 171.0 |
| Kansas City Power and Light Company [Member] | ||
| Accounts receivable pledged as collateral | 110.0 | 110.0 |
| Collateralized note payable | 110.0 | $ 110.0 |
| Maximum amount of outstanding principal under receivables agreement | 110.0 | |
| KCPL Greater Missouri Operations [Member] | ||
| Maximum amount of outstanding principal under receivables agreement from mid-November to mid-June | 65.0 | |
| Maximum amount of outstanding principal under receivables agreement from mid-June to mid-November | $ 80.0 |
| X | ||||||||||
- Definition Maximum amount of outstanding principal under receivables agreement No definition available.
|
| X | ||||||||||
- Definition MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidJunToMidNov No definition available.
|
| X | ||||||||||
- Definition MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidNovToMidJun No definition available.
|
| X | ||||||||||
- Definition Carrying amount of financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying amount of liabilities associated with financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Nuclear Plant (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Investments in decommissioning trust fund [Line Items] | |||
| Cost Basis | $ 152.8 | $ 145.4 | |
| Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 50.5 | 54.4 | |
| Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (2.6) | (0.8) | |
| Fair Value, Nuclear decommissioning trust fund | $ 200.7 | 199.0 | $ 183.9 |
| Weighted average maturity of debt securities (in years) | 8 years | ||
| Realized gains on investments in decommissioning trust fund | $ 5.3 | 1.4 | 2.4 |
| Realized losses on investments in decommissioning trust fund | (4.6) | (1.0) | (0.7) |
| Equity Securities [Member] | |||
| Investments in decommissioning trust fund [Line Items] | |||
| Cost Basis | 89.6 | 87.2 | |
| Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax | 47.9 | 50.6 | |
| Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax | (2.1) | (0.7) | |
| Fair Value, Nuclear decommissioning trust fund | 135.4 | 137.1 | |
| Debt Securities [Member] | |||
| Investments in decommissioning trust fund [Line Items] | |||
| Cost Basis | 59.6 | 55.4 | |
| Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax | 2.6 | 3.8 | |
| Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax | (0.5) | (0.1) | |
| Fair Value, Nuclear decommissioning trust fund | 61.7 | 59.1 | |
| Other Securities [Member] | |||
| Investments in decommissioning trust fund [Line Items] | |||
| Cost Basis | 3.6 | 2.8 | |
| Fair Value, Nuclear decommissioning trust fund | 3.6 | 2.8 | |
| Kansas City Power and Light Company [Member] | |||
| Investments in decommissioning trust fund [Line Items] | |||
| Fair Value, Nuclear decommissioning trust fund | $ 200.7 | $ 199.0 | $ 183.9 |
| X | ||||||||||
- Definition This represents the weighted average number of years when the debt securities held in the decommissioning trust fund are scheduled to be fully repaid. No definition available.
|
| X | ||||||||||
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Nuclear Plant Decommissioning Trust (Details) - USD ($) $ in Millions |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
||||
| Nuclear decommissioning trust fund [Roll Forward] | |||||
| Nuclear decommissioning trust fund, beginning balance | $ 199.0 | $ 183.9 | |||
| Contributions to nuclear decommissioning trust fund | 3.3 | 3.3 | |||
| Earned income, net of fees | 3.4 | 3.6 | |||
| Net realized gains (losses) on nuclear decommissioning trust fund | 0.7 | 0.4 | |||
| Net unrealized gains (losses) on nuclear decommissioning trust fund | (5.7) | 7.8 | |||
| Nuclear decommissioning trust fund, ending balance | $ 200.7 | 199.0 | |||
| Wolf Creek [Member] | |||||
| Jointly Owned Utility Plant Interests [Line Items] | |||||
| Ownership percentage in Wolf Creek, a nuclear generating unit (in hundredths) | 47.00% | ||||
| Nuclear Insurance [Abstract] | |||||
| Industry aggregate limit on nuclear insurance for property claims including accidental damages | $ 3,200.0 | ||||
| Industry aggregate limit on non-nuclear acts of terrorism | 1,800.0 | ||||
| Amount of insurance against public liability claims resulting from nuclear incidents to full limit of public liability | 13,500.0 | ||||
| Maximum available commercial insurance | 400.0 | ||||
| Remaining balance provided through industry wide retrospective assesment program mandated by law | 13,100.0 | ||||
| Maximum amount able to be assessed to owners | 127.3 | ||||
| SFP Program-annual amount payable per incident | 19.0 | ||||
| Amount of decontamination liability, premature decommissioning liability and property damage insurance | 2,800.0 | ||||
| Premature decommissioning coverage applies only if property damage exceeds this amount and trust funds have been exhausted | 500.0 | ||||
| Estimated maximum amount of retrospective assessments under the current policies | 42.2 | ||||
| Wolf Creek [Member] | Missouri Public Service Commission [Member] | |||||
| Nuclear Plant Decommissioning Costs [Abstract] | |||||
| Current cost of decommissioning (in 2014 dollars) | 765.1 | ||||
| Future cost of decommissioning (in 2045 through 2053 dollars) | $ 2,253.1 | ||||
| Annual Escalation Factor | 3.22% | ||||
| Annual return on trust assets through 2025 | [1] | 5.89% | |||
| Annual return on trusts assets in 2053 | 2.22% | ||||
| Wolf Creek [Member] | Kansas Corporation Commission [Member] | |||||
| Nuclear Plant Decommissioning Costs [Abstract] | |||||
| Current cost of decommissioning (in 2014 dollars) | $ 765.1 | ||||
| Future cost of decommissioning (in 2045 through 2053 dollars) | $ 2,201.5 | ||||
| Annual Escalation Factor | 3.15% | ||||
| Annual return on trust assets through 2025 | [1] | 6.43% | |||
| Annual return on trusts assets in 2053 | 0.72% | ||||
| Kansas City Power and Light Company [Member] | |||||
| Nuclear decommissioning trust fund [Roll Forward] | |||||
| Nuclear decommissioning trust fund, beginning balance | $ 199.0 | 183.9 | |||
| Contributions to nuclear decommissioning trust fund | 3.3 | 3.3 | |||
| Earned income, net of fees | 3.4 | 3.6 | |||
| Net realized gains (losses) on nuclear decommissioning trust fund | 0.7 | 0.4 | |||
| Net unrealized gains (losses) on nuclear decommissioning trust fund | (5.7) | 7.8 | |||
| Nuclear decommissioning trust fund, ending balance | $ 200.7 | $ 199.0 | |||
| Kansas City Power and Light Company [Member] | Wolf Creek [Member] | |||||
| Jointly Owned Utility Plant Interests [Line Items] | |||||
| Ownership percentage in Wolf Creek, a nuclear generating unit (in hundredths) | 47.00% | ||||
| Nuclear Insurance [Abstract] | |||||
| Maximum amount able to be assessed to owners | $ 59.8 | ||||
| SFP Program-annual amount payable per incident | 8.9 | ||||
| Amount of decontamination liability, premature decommissioning liability and property damage insurance | 1,300.0 | ||||
| Estimated maximum amount of retrospective assessments under the current policies | 22.4 | ||||
| Kansas City Power and Light Company [Member] | Wolf Creek [Member] | Missouri Public Service Commission [Member] | |||||
| Nuclear Plant Decommissioning Costs [Abstract] | |||||
| Current cost of decommissioning (in 2014 dollars) | 359.6 | ||||
| Future cost of decommissioning (in 2045 through 2053 dollars) | 1,059.0 | ||||
| Kansas City Power and Light Company [Member] | Wolf Creek [Member] | Kansas Corporation Commission [Member] | |||||
| Nuclear Plant Decommissioning Costs [Abstract] | |||||
| Current cost of decommissioning (in 2014 dollars) | 359.6 | ||||
| Future cost of decommissioning (in 2045 through 2053 dollars) | $ 1,034.7 | ||||
| |||||
| X | ||||||||||
- Definition Amount of decontamination liability, premature decommissioning liability and property damage insurance. No definition available.
|
| X | ||||||||||
- Definition Amount of insurance against public liability claims resulting from nuclear incidents to the full limit of public liability. No definition available.
|
| X | ||||||||||
- Definition Annual escalation factor applied to decommissioning costs in current year dollars to arrive at future costs of decommissioning. No definition available.
|
| X | ||||||||||
- Definition This represents the expected rate of return on assets held in the nuclear decommissioning trust through 2025. No definition available.
|
| X | ||||||||||
- Definition The expected rate of return on assets held in the nuclear decommissioning trust is expected to decline to this amount after 2025 through 2053 as the fund's investment mix will increasingly become more conservative as the decommissioning period approaches. No definition available.
|
| X | ||||||||||
- Definition This represents total contributions to the decommissioning trust fund during the current period. No definition available.
|
| X | ||||||||||
- Definition Represents the current cost of decommissioning the Wolf Creek generation station. No definition available.
|
| X | ||||||||||
- Definition This represents income earned, net of fees, on decommissioning trust fund investments during the current period. No definition available.
|
| X | ||||||||||
- Definition Estimated maximum amount of retrospective assessments under the current policies. No definition available.
|
| X | ||||||||||
- Definition This represents the cost of decommissioning the Wolf Creek generating station in expected dollars at the time of decommissioning. No definition available.
|
| X | ||||||||||
- Definition Industry aggregate limit for property claims related to non-nuclear acts of terrorism. No definition available.
|
| X | ||||||||||
- Definition Industry aggregate limit on nuclear insurance for property claims related to nuclear acts of terrorism including accidental outage power costs. No definition available.
|
| X | ||||||||||
- Definition Maximum amount able to be assessed to owners. No definition available.
|
| X | ||||||||||
- Definition Maximum available commercial insurance. No definition available.
|
| X | ||||||||||
- Definition This represents the net realized gains (losses) on decommissioning trust fund investments during the current period. No definition available.
|
| X | ||||||||||
- Definition This represents the net unrealized gains (losses) on decommissioning trust fund investments during the current period. No definition available.
|
| X | ||||||||||
- Definition Nuclear decommissioning trust fund [Roll Forward] No definition available.
|
| X | ||||||||||
- Definition Nuclear Insurance [Abstract] No definition available.
|
| X | ||||||||||
- Definition Nuclear Plant Decommissioning Costs [Abstract] No definition available.
|
| X | ||||||||||
- Definition Premature decommissioning coverage applies only if property damage exceeds this amount and trust funds have been exhausted. No definition available.
|
| X | ||||||||||
- Definition Remaining balance of public liability limits provided through industry wide retrospective assesment program mandated by law. No definition available.
|
| X | ||||||||||
- Definition Under the Secondary Financial Protection (SPF) program, amount that owners can be assessed per nuclear incident per year. No definition available.
|
| X | ||||||||||
- Definition Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The proportionate share of interest (percent) in a jointly owned utility plant. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Regulatory Matters (Details) - Kansas City Power and Light Company [Member] - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2015 |
Jan. 31, 2015 |
Oct. 31, 2014 |
Dec. 31, 2015 |
|
| Missouri Public Service Commission [Member] | ||||
| Regulatory Proceedings [Line Items] | ||||
| Annual revenue increase, requested | $ 120.9 | |||
| Revised annual revenue increase, requested | $ 112.7 | |||
| Return on equity, requested (in hundredths) | 10.30% | |||
| Rate-making equity ratio, requested (in hundredths) | 50.36% | |||
| Annual revenue increase authorized | $ 89.7 | |||
| Return on equity, approved (in hundredths) | 9.50% | |||
| Ratemaking equity ratio, approved (in hundredths) | 50.09% | |||
| Kansas Corporation Commission [Member] | ||||
| Regulatory Proceedings [Line Items] | ||||
| Annual revenue increase, requested | $ 67.3 | |||
| Return on equity, requested (in hundredths) | 10.30% | |||
| Rate-making equity ratio, requested (in hundredths) | 50.48% | |||
| Annual revenue increase authorized | $ 48.7 | |||
| Return on equity, approved (in hundredths) | 9.30% | |||
| Ratemaking equity ratio, approved (in hundredths) | 50.48% | |||
| X | ||||||||||
- Definition Percentage of public utility's approved equity to capital, including debt and equity. No definition available.
|
| X | ||||||||||
- Definition Amount of public utility's approved rate increase (decrease) by regulatory agency. No definition available.
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of public utility's requested equity to capital, including debt and equity. No definition available.
|
| X | ||||||||||
- Definition Amount of public utility's amended requested rate increase (decrease) with regulatory agency. No definition available.
|
| X | ||||||||||
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. No definition available.
|
| X | ||||||||||
- Definition Percentage of public utility's requested return on equity. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Regulatory Matters Asset (Details) - USD ($) $ in Millions |
12 Months Ended | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 979.1 | $ 1,034.6 | |||||||||||||||||||
| Taxes recoverable through future rates [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 151.4 | 133.4 | |||||||||||||||||||
| Loss on reacquired debt [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 13.5 | 10.9 | |||||||||||||||||||
| Removal Costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 12.9 | 2.8 | |||||||||||||||||||
| Asset Retirement Obligation Costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 77.4 | 55.3 | |||||||||||||||||||
| Pension and post-retirement costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 457.4 | 525.9 | |||||||||||||||||||
| Deferred customer programs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 71.1 | 69.6 | |||||||||||||||||||
| Rate case expenses [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 1.3 | 1.5 | |||||||||||||||||||
| Fuel recovery mechanisms [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 16.4 | 54.0 | |||||||||||||||||||
| Derivative instruments [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 6.8 | 2.8 | |||||||||||||||||||
| Iatan No. 1 and Common facilities depreciation and carrying costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 19.3 | 20.2 | |||||||||||||||||||
| Iatan No. 2 construction accounting costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 44.7 | 43.4 | |||||||||||||||||||
| Kansas property tax surcharge [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 6.8 | 6.1 | |||||||||||||||||||
| Solar Rebates [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 82.6 | 86.0 | |||||||||||||||||||
| Transmission Delivery Charge [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 1.7 | 0.0 | |||||||||||||||||||
| LaCygne Deferred Depreciation [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 2.9 | 0.0 | |||||||||||||||||||
| Other Regulatory Assets (Liabilities) [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 12.9 | 22.7 | |||||||||||||||||||
| Kansas City Power and Light Company [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 732.4 | 745.7 | |||||||||||||||||||
| Kansas City Power and Light Company [Member] | Taxes recoverable through future rates [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 125.0 | 107.1 | |||||||||||||||||||
| Kansas City Power and Light Company [Member] | Loss on reacquired debt [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 11.3 | [1] | 8.1 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | Removal Costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 12.9 | 2.8 | |||||||||||||||||||
| Kansas City Power and Light Company [Member] | Asset Retirement Obligation Costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 57.9 | 38.1 | |||||||||||||||||||
| Kansas City Power and Light Company [Member] | Pension and post-retirement costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 358.5 | [2] | 430.5 | ||||||||||||||||||
| Amount not included in rate base | 343.7 | ||||||||||||||||||||
| Kansas City Power and Light Company [Member] | Deferred customer programs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 50.3 | [3] | 50.8 | ||||||||||||||||||
| Amount not included in rate base | 8.3 | ||||||||||||||||||||
| Kansas City Power and Light Company [Member] | Rate case expenses [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 1.3 | [4] | 1.4 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | Fuel recovery mechanisms [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 16.3 | [4] | 13.0 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | Derivative instruments [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 0.5 | [5] | 0.2 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | Iatan No. 1 and Common facilities depreciation and carrying costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 14.1 | [6] | 14.7 | ||||||||||||||||||
| Regulatory Noncurrent Asset, End Date for Recovery | Dec. 31, 2038 | ||||||||||||||||||||
| Kansas City Power and Light Company [Member] | Iatan No. 2 construction accounting costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 28.7 | [7] | 28.1 | ||||||||||||||||||
| Regulatory Noncurrent Asset, End Date for Recovery | Dec. 31, 2058 | ||||||||||||||||||||
| Kansas City Power and Light Company [Member] | Kansas property tax surcharge [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 6.8 | [4] | 6.1 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | Solar Rebates [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 33.6 | [4] | 29.1 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | Transmission Delivery Charge [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 1.7 | [4] | 0.0 | ||||||||||||||||||
| Kansas City Power and Light Company [Member] | LaCygne Deferred Depreciation [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 2.9 | [8] | 0.0 | ||||||||||||||||||
| Regulatory Noncurrent Asset, End Date for Recovery | Dec. 31, 2040 | ||||||||||||||||||||
| Kansas City Power and Light Company [Member] | Other Regulatory Assets (Liabilities) [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 10.6 | [4] | 15.7 | ||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 246.7 | 288.9 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Taxes recoverable through future rates [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 26.4 | 26.3 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Loss on reacquired debt [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 2.2 | [1] | 2.8 | ||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Removal Costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 0.0 | 0.0 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Asset Retirement Obligation Costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 19.5 | 17.2 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Pension and post-retirement costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 98.9 | [2] | 95.4 | ||||||||||||||||||
| Amount not included in rate base | 54.5 | ||||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Deferred customer programs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 20.8 | [9] | 18.8 | ||||||||||||||||||
| Amount not included in rate base | 7.4 | ||||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Rate case expenses [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 0.0 | 0.1 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Fuel recovery mechanisms [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 0.1 | [4] | 41.0 | ||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Derivative instruments [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 6.3 | [5] | 2.6 | ||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Iatan No. 1 and Common facilities depreciation and carrying costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 5.2 | [6] | 5.5 | ||||||||||||||||||
| Regulatory Noncurrent Asset, End Date for Recovery | Dec. 31, 2038 | ||||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Iatan No. 2 construction accounting costs [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 16.0 | [7] | 15.3 | ||||||||||||||||||
| Regulatory Noncurrent Asset, End Date for Recovery | Dec. 31, 2058 | ||||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Kansas property tax surcharge [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 0.0 | 0.0 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Solar Rebates [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 49.0 | [4] | 56.9 | ||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Transmission Delivery Charge [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 0.0 | 0.0 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | LaCygne Deferred Depreciation [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | 0.0 | 0.0 | |||||||||||||||||||
| KCPL Greater Missouri Operations [Member] | Other Regulatory Assets (Liabilities) [Member] | |||||||||||||||||||||
| Regulatory Assets [Line Items] | |||||||||||||||||||||
| Regulatory Assets, Noncurrent | $ 2.3 | [4] | $ 7.0 | ||||||||||||||||||
| |||||||||||||||||||||
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition End date for recovery of the regulatory noncurrent asset, in CCYY-MM-DD format. No definition available.
|
| X | ||||||||||
- Definition Remaining balance of regulatory assets for which no return on investment during recovery is provided. In some cases, a regulator may permit an enterprise to include a cost that would be charged to expense by an unregulated enterprise as an allowable cost over a period of time by amortizing that cost for rate-making purposes, but the regulator does not include the unrecovered amount in the rate base. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Regulatory Matters Liabilities (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|||
|---|---|---|---|---|---|
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | $ 284.4 | $ 282.7 | |||
| Emission allowances [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 66.1 | 70.1 | |||
| Asset retirement obligations [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 86.5 | 93.9 | |||
| Removal Costs [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 68.2 | 69.7 | |||
| Other Regulatory Assets (Liabilities) [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 63.6 | 49.0 | |||
| Kansas City Power and Light Company [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 164.6 | 172.0 | |||
| Kansas City Power and Light Company [Member] | Emission allowances [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 66.1 | 70.1 | |||
| Kansas City Power and Light Company [Member] | Asset retirement obligations [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 86.5 | 93.9 | |||
| Kansas City Power and Light Company [Member] | Removal Costs [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 0.0 | 0.0 | |||
| Kansas City Power and Light Company [Member] | Other Regulatory Assets (Liabilities) [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 12.0 | 8.0 | |||
| KCPL Greater Missouri Operations [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 119.8 | 110.7 | |||
| KCPL Greater Missouri Operations [Member] | Emission allowances [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 0.0 | 0.0 | |||
| KCPL Greater Missouri Operations [Member] | Asset retirement obligations [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 0.0 | 0.0 | |||
| KCPL Greater Missouri Operations [Member] | Removal Costs [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | 68.2 | [1] | 69.7 | ||
| KCPL Greater Missouri Operations [Member] | Other Regulatory Assets (Liabilities) [Member] | |||||
| Regulatory Liabilities [Line Items] | |||||
| Regulatory liabilities | $ 51.6 | $ 41.0 | |||
| |||||
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| X | ||||||||||
- Definition The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Regulatory Matters Regulatory Matters Subsequent Events (Details) - Kcpl Greater Missouri Operations Member - MissouriPublicServiceCommission [Member] - Subsequent Event [Member] $ in Millions |
1 Months Ended |
|---|---|
|
Feb. 29, 2016
USD ($)
| |
| Subsequent Event [Line Items] | |
| Annual revenue increase, requested | $ 59.3 |
| Return on equity, requested (in hundredths) | 9.90% |
| Rate-making equity ratio, requested (in hundredths) | 54.83% |
| X | ||||||||||
- Definition Percentage of public utility's requested equity to capital, including debt and equity. No definition available.
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| X | ||||||||||
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. No definition available.
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| X | ||||||||||
- Definition Percentage of public utility's requested return on equity. No definition available.
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| X | ||||||||||
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. No definition available.
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
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Goodwill and Intangible Assets Goodwill (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Goodwill [Line Items] | ||
| Goodwill | $ 169.0 | $ 169.0 |
| X | ||||||||||
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
Intangibles Assets (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of Intangible Assets | $ 28.6 | $ 21.6 |
| Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months | 21.9 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Two | 18.7 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Three | 16.5 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Four | 14.5 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Five | 12.4 | |
| Kansas City Power and Light Company [Member] | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of Intangible Assets | 24.7 | 19.2 |
| Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months | 18.9 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Two | 17.7 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Three | 16.1 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Four | 14.1 | |
| Finite-Lived Intangible Assets, Amortization Expense, Year Five | 12.0 | |
| Computer Software, Intangible Asset [Member] | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Finite-Lived Intangible Assets, Gross | 333.0 | 300.2 |
| Finite-Lived Intangible Assets, Accumulated Amortization | (191.8) | (190.9) |
| Computer Software, Intangible Asset [Member] | Kansas City Power and Light Company [Member] | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Finite-Lived Intangible Assets, Gross | 315.5 | 277.9 |
| Finite-Lived Intangible Assets, Accumulated Amortization | (177.7) | (175.5) |
| Asset Improvements [Member] | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Finite-Lived Intangible Assets, Gross | 28.3 | 27.4 |
| Finite-Lived Intangible Assets, Accumulated Amortization | (6.1) | (5.5) |
| Asset Improvements [Member] | Kansas City Power and Light Company [Member] | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Finite-Lived Intangible Assets, Gross | 13.1 | 12.2 |
| Finite-Lived Intangible Assets, Accumulated Amortization | $ (1.5) | $ (1.3) |
| X | ||||||||||
- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Asset Retirement Obligations (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |
|---|---|---|---|
Jun. 30, 2015 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Increase in asset retirement obligations due to CCR regulations | $ 69.5 | ||
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||
| Asset Retirement Obligation, Beginning Balance | $ 195.9 | $ 158.8 | |
| Additions | 54.5 | 0.0 | |
| Revision in timing and/or estimates | 20.5 | 26.8 | |
| Settlements | (7.8) | 0.0 | |
| Accretion | 12.8 | 10.3 | |
| Asset Retirement Obligation, Ending Balance | $ 275.9 | 195.9 | |
| Asset Retirement Obligations, Liability Not Recognized | certain wiring used in Great Plains Energy's and KCP&L's generating stations include asbestos insulation, which would require special handling if disturbed. Due to the inability to reasonably estimate the quantities or the amount of disturbance that will be necessary during dismantlement at the end of the life of a plant, the fair value of this ARO cannot be reasonably estimated at this time. Management will continue to monitor the obligation and will recognize a liability in the period in which sufficient information becomes available to reasonably estimate its fair value. | ||
| Kansas City Power and Light Company [Member] | |||
| Asset Retirement Obligations, Description | KCP&L has AROs related to decommissioning Wolf Creek, site remediation of its Spearville Wind Energy Facilities, asbestos abatement, removal of storage tanks and closure and post-closure of ponds and landfills containing coal combustion residuals (CCRs). | ||
| Increase in asset retirement obligations due to CCR regulations | $ 51.3 | ||
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||
| Asset Retirement Obligation, Beginning Balance | $ 177.7 | 141.7 | |
| Additions | 34.6 | 0.0 | |
| Revision in timing and/or estimates | 22.2 | 26.8 | |
| Settlements | (6.7) | 0.0 | |
| Accretion | 11.5 | 9.2 | |
| Asset Retirement Obligation, Ending Balance | $ 239.3 | $ 177.7 | |
| Asset Retirement Obligations, Liability Not Recognized | certain wiring used in Great Plains Energy's and KCP&L's generating stations include asbestos insulation, which would require special handling if disturbed. Due to the inability to reasonably estimate the quantities or the amount of disturbance that will be necessary during dismantlement at the end of the life of a plant, the fair value of this ARO cannot be reasonably estimated at this time. Management will continue to monitor the obligation and will recognize a liability in the period in which sufficient information becomes available to reasonably estimate its fair value. | ||
| KCPL Greater Missouri Operations [Member] | |||
| Asset Retirement Obligations, Description | GMO has AROs related to asbestos abatement, removal of storage tanks and closure and post-closure of ponds and landfills containing CCRs. | ||
| X | ||||||||||
- Definition Total increase in asset retirement obligations (ARO's) due to Coal Combustion Residual (CCR) regulations enacted by the EPA. The increase includes both newly created ARO's and revisions to existing ARO's No definition available.
|
| X | ||||||||||
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of asset retirement obligations incurred during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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| X | ||||||||||
- Definition A general description of the asset retirement obligations and the associated long-lived assets. Description may include the terms of the legal restriction. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Description of an asset retirement obligation for which a liability has not been recognized because fair value cannot be reasonably estimated and the reasons why fair value cannot be reasonably estimated. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Pension Plans and Other Employee Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|||
| Amounts recognized in the consolidated balance sheets [Abstract] | |||||
| Pension and Other Postretirement Defined Benefit Plans, Current Liabilities | $ (3.4) | $ (2.8) | |||
| Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent | (455.2) | (508.6) | |||
| Pension plans with the accumulated benefit obligation in excess of plans assets [Abstract] | |||||
| Unfunded accumulated benefit obligation for GMO SERP | 22.9 | ||||
| Segregated assets for GMO SERP | 16.4 | ||||
| Employee Savings Plans [Abstract] | |||||
| Defined contribution savings plan, cost of plan | 10.6 | 9.7 | $ 9.6 | ||
| Kansas City Power and Light Company [Member] | |||||
| Amounts recognized in the consolidated balance sheets [Abstract] | |||||
| Pension and Other Postretirement Defined Benefit Plans, Current Liabilities | (2.0) | (1.5) | |||
| Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent | (433.4) | (485.4) | |||
| Employee Savings Plans [Abstract] | |||||
| Defined contribution savings plan, cost of plan | 7.9 | 7.1 | 7.0 | ||
| Pension Plans, Defined Benefit [Member] | |||||
| Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] | |||||
| Defined Benefit Plan, Benefit Obligation | 1,186.8 | 1,007.4 | |||
| Defined Benefit Plan, Service Cost | 45.3 | 36.7 | 41.2 | ||
| Defined Benefit Plan, Interest Cost | 50.3 | 50.1 | 47.2 | ||
| Defined Benefit Plan, Contributions by Plan Participants | 0.0 | 0.0 | |||
| Defined Benefit Plan, Plan Amendments | 0.0 | 0.0 | |||
| Actuarial (gain) loss | (59.4) | 181.1 | |||
| Defined Benefit Plan, Benefits Paid | (68.2) | (49.0) | |||
| Defined Benefit Plan, Settlements, Benefit Obligation | 0.0 | (39.5) | |||
| Defined Benefit Plan, Benefit Obligation | 1,154.8 | 1,186.8 | 1,007.4 | ||
| Change in plan assets [Roll Forward] | |||||
| Fair value of plan assets at beginning of the year | 730.0 | 703.0 | |||
| Actual return on plan assets | (16.3) | 47.2 | |||
| Defined benefit plan, contributions by employer and participants | 76.9 | 66.2 | |||
| Defined benefit plan benefits paid portion paid from plan assets | (66.7) | (46.9) | |||
| Defined Benefit Plan, Settlements, Plan Assets | 0.0 | (39.5) | |||
| Fair value of plan assets at end of the year | 723.9 | 730.0 | 703.0 | ||
| Funded status at end of year | (430.9) | (456.8) | |||
| Amounts recognized in the consolidated balance sheets [Abstract] | |||||
| Defined Benefit Plan, Assets for Plan Benefits, Noncurrent | 0.0 | 0.0 | |||
| Pension and Other Postretirement Defined Benefit Plans, Current Liabilities | (2.6) | (1.9) | |||
| Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent | (428.3) | (454.9) | |||
| Defined Benefit Plan Amounts Recognized in Balance Sheet before Regulatory Treatment | (430.9) | (456.8) | |||
| Defined benefit plan amount recognized in Accumulated Other Comprehensive Income or regulatory asset/liability | 461.2 | 500.5 | |||
| Defined Benefit Plan, Amounts Recognized in Balance Sheet | 30.3 | 43.7 | |||
| Amounts in accumulated other comprehensive income or regulatory asset/liability not yet recognized as a component of net periodic benefit cost [Abstract] | |||||
| Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Gains/Losses Before Tax | 230.7 | 273.5 | |||
| Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Prior Service Cost Credit Before Tax | 3.9 | 4.7 | |||
| Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Transition Obligation Before Tax | 0.0 | 0.0 | |||
| Defined Benefit Plan Accumulated Other Comprehensive Income Other Before Tax | 226.6 | 222.3 | |||
| Defined benefit plan amount recognized in Accumulated Other Comprehensive Income or regulatory asset/liability | 461.2 | 500.5 | |||
| Components of net periodic benefit costs [Abstract] | |||||
| Defined Benefit Plan, Service Cost | 45.3 | 36.7 | 41.2 | ||
| Defined Benefit Plan, Interest Cost | 50.3 | 50.1 | 47.2 | ||
| Defined Benefit Plan, Expected Return on Plan Assets | (51.7) | (50.2) | (47.1) | ||
| Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | 0.8 | 0.9 | 2.0 | ||
| Defined Benefit Plan, Amortization of (Gains) Losses | 51.4 | 50.0 | 54.3 | ||
| Defined Benefit Plan, Amortization of Transition Obligations (Assets) | 0.0 | 0.0 | 0.0 | ||
| Settlement charges | 0.0 | 8.5 | 4.9 | ||
| Net periodic benefit costs before regulatory adjustment | 96.1 | 96.0 | 102.5 | ||
| Defined Benefit Plan, Regulatory Adjustment | (9.8) | (11.3) | (16.8) | ||
| Defined Benefit Plan, Net Periodic Benefit Cost | 86.3 | 84.7 | 85.7 | ||
| Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income Regulatory Assets/Liabilities [Abstract] | |||||
| Net (gain) loss arising during period | 8.6 | 175.8 | (147.0) | ||
| Amortization of net gains (losses) included in net periodic benefit costs | (51.4) | (50.0) | (54.3) | ||
| Prior service cost | 0.0 | 0.0 | 0.3 | ||
| Amortization of prior service cost | (0.8) | (0.9) | (2.0) | ||
| Amortization of transition obligation | 0.0 | 0.0 | 0.0 | ||
| Other regulatory activity | 4.3 | 7.3 | 11.8 | ||
| Total Recognized In Other Comprehensive Income Or Regulatory Asset/Liability | (39.3) | 132.2 | (191.2) | ||
| Total Recognized In Net Periodic Benefit Costs And Other Comprehensive Income Or Regulatory Asset/Liability | 47.0 | 216.9 | (105.5) | ||
| Estimated prior service cost that will be amortized in the next fiscal year | 0.7 | ||||
| Net (gain) loss for the defined benefit plans that will be amortized in the next fiscal year | $ 51.8 | ||||
| Length Of Time For Amortization Of Net Actuarial Gains And Losses For Financial Reporting Purposes | rolling five-year average | ||||
| Length Of Time For Amortization Of Net Actuarial Gains And Losses For Regulatory Reporting Purposes | ten years | ||||
| Accumulated benefit obligation (ABO) for all defined benefit plans | $ 1,017.6 | 1,036.8 | |||
| Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets [Abstract] | |||||
| Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Benefit Obligation | 1,154.8 | 1,186.8 | |||
| Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets | 723.9 | 730.0 | |||
| Pension plans with the accumulated benefit obligation in excess of plans assets [Abstract] | |||||
| Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation | 1,017.6 | 1,036.8 | |||
| Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets | $ 723.9 | $ 730.0 | |||
| Weighted average assumptions used to determine the benefit obligation [Abstract] | |||||
| Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate | 4.54% | 4.22% | |||
| Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase | 3.62% | 3.62% | |||
| Defined Benefit Plan, Assumptions Used in Calculations, Narrative Description | The expected long-term rate of return on plan assets represents Great Plains Energy's estimate of the long-term return on plan assets and is based on historical and projected rates of return for current and planned asset classes in the plans' investment portfolios. Assumed projected rates of return for each asset class were selected after analyzing historical experience and future expectations of the returns of various asset classes. Based on the target asset allocation for each asset class, the overall expected rate of return for the portfolios was developed and adjusted for the effect of projected benefits paid from plan assets and future plan contributions. | ||||
| Weighted average assumptions used to determine net costs [Abstract] | |||||
| Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate | 4.22% | 5.03% | |||
| Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets | 7.14% | 7.24% | |||
| Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 3.62% | 3.69% | |||
| Contribute to plans in next year | $ 75.7 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months | 81.2 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Two | 77.2 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Three | 77.4 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Four | 80.5 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Five | 82.5 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter | $ 427.3 | ||||
| Defined Benefit Plan, Target Allocation Percentage | The portfolios are invested, and periodically rebalanced, to achieve targeted allocations of approximately 33% U.S. large cap and small cap equity securities, 20% international equity securities, 35% fixed income securities, 7% real estate, 1% commodities and 4% hedge funds. | ||||
| Defined Benefit Plan, Investment Strategies, Investment Fund Category | The investment strategy supports the objective of the fund, which is to earn the highest possible return on plan assets within a reasonable and prudent level of risk. | ||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | |||||
| Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] | |||||
| Defined Benefit Plan, Benefit Obligation | $ 165.2 | $ 160.5 | |||
| Defined Benefit Plan, Service Cost | 3.3 | 3.7 | 4.4 | ||
| Defined Benefit Plan, Interest Cost | 6.8 | 7.9 | 7.7 | ||
| Defined Benefit Plan, Contributions by Plan Participants | 6.9 | 6.8 | |||
| Defined Benefit Plan, Plan Amendments | (7.1) | 0.0 | |||
| Actuarial (gain) loss | (23.6) | (0.3) | |||
| Defined Benefit Plan, Benefits Paid | (14.0) | (13.4) | |||
| Defined Benefit Plan, Settlements, Benefit Obligation | 0.0 | 0.0 | |||
| Defined Benefit Plan, Benefit Obligation | 137.5 | 165.2 | 160.5 | ||
| Change in plan assets [Roll Forward] | |||||
| Fair value of plan assets at beginning of the year | 110.6 | 101.2 | |||
| Actual return on plan assets | (0.1) | 4.1 | |||
| Defined benefit plan, contributions by employer and participants | 17.6 | 18.6 | |||
| Defined benefit plan benefits paid portion paid from plan assets | (13.8) | (13.3) | |||
| Defined Benefit Plan, Settlements, Plan Assets | 0.0 | 0.0 | |||
| Fair value of plan assets at end of the year | 114.3 | 110.6 | 101.2 | ||
| Funded status at end of year | (23.2) | (54.6) | |||
| Amounts recognized in the consolidated balance sheets [Abstract] | |||||
| Defined Benefit Plan, Assets for Plan Benefits, Noncurrent | 4.5 | 0.0 | |||
| Pension and Other Postretirement Defined Benefit Plans, Current Liabilities | (0.8) | (0.9) | |||
| Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent | (26.9) | (53.7) | |||
| Defined Benefit Plan Amounts Recognized in Balance Sheet before Regulatory Treatment | (23.2) | (54.6) | |||
| Defined benefit plan amount recognized in Accumulated Other Comprehensive Income or regulatory asset/liability | (9.4) | 26.1 | |||
| Defined Benefit Plan, Amounts Recognized in Balance Sheet | (32.6) | (28.5) | |||
| Amounts in accumulated other comprehensive income or regulatory asset/liability not yet recognized as a component of net periodic benefit cost [Abstract] | |||||
| Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Gains/Losses Before Tax | (3.3) | 17.5 | |||
| Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Prior Service Cost Credit Before Tax | 3.4 | 13.5 | |||
| Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Transition Obligation Before Tax | 0.0 | 0.2 | |||
| Defined Benefit Plan Accumulated Other Comprehensive Income Other Before Tax | (9.5) | (5.1) | |||
| Defined benefit plan amount recognized in Accumulated Other Comprehensive Income or regulatory asset/liability | (9.4) | 26.1 | |||
| Components of net periodic benefit costs [Abstract] | |||||
| Defined Benefit Plan, Service Cost | 3.3 | 3.7 | 4.4 | ||
| Defined Benefit Plan, Interest Cost | 6.8 | 7.9 | 7.7 | ||
| Defined Benefit Plan, Expected Return on Plan Assets | (2.9) | (2.6) | (2.0) | ||
| Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | 3.1 | 3.1 | 7.2 | ||
| Defined Benefit Plan, Amortization of (Gains) Losses | 0.2 | (0.1) | 1.7 | ||
| Defined Benefit Plan, Amortization of Transition Obligations (Assets) | 0.2 | 0.2 | 0.2 | ||
| Settlement charges | 0.0 | 0.0 | 0.0 | ||
| Net periodic benefit costs before regulatory adjustment | 10.7 | 12.2 | 19.2 | ||
| Defined Benefit Plan, Regulatory Adjustment | 4.4 | 4.3 | (2.4) | ||
| Defined Benefit Plan, Net Periodic Benefit Cost | 15.1 | 16.5 | 16.8 | ||
| Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income Regulatory Assets/Liabilities [Abstract] | |||||
| Net (gain) loss arising during period | (20.6) | (1.8) | (22.1) | ||
| Amortization of net gains (losses) included in net periodic benefit costs | (0.2) | 0.1 | (1.7) | ||
| Prior service cost | (7.0) | 0.0 | (6.0) | ||
| Amortization of prior service cost | (3.1) | (3.1) | (7.2) | ||
| Amortization of transition obligation | (0.2) | (0.2) | (0.2) | ||
| Other regulatory activity | (4.4) | (4.2) | 2.1 | ||
| Total Recognized In Other Comprehensive Income Or Regulatory Asset/Liability | (35.5) | (9.2) | (35.1) | ||
| Total Recognized In Net Periodic Benefit Costs And Other Comprehensive Income Or Regulatory Asset/Liability | (20.4) | 7.3 | $ (18.3) | ||
| Estimated prior service cost that will be amortized in the next fiscal year | 1.2 | ||||
| Net (gain) loss for the defined benefit plans that will be amortized in the next fiscal year | (1.5) | ||||
| Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets [Abstract] | |||||
| Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Benefit Obligation | 108.5 | 165.2 | |||
| Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets | $ 80.8 | $ 110.6 | |||
| Weighted average assumptions used to determine the benefit obligation [Abstract] | |||||
| Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate | 4.47% | 4.14% | |||
| Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase | 3.50% | 3.50% | |||
| Weighted average assumptions used to determine net costs [Abstract] | |||||
| Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate | 4.14% | 4.92% | |||
| Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets | [1] | 2.81% | 2.70% | ||
| Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 3.50% | 3.50% | |||
| Contribute to plans in next year | $ 5.1 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months | 8.2 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Two | 8.8 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Three | 9.5 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Four | 10.2 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Year Five | 10.8 | ||||
| Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter | $ 60.4 | ||||
| Defined Benefit Plan, Investment Strategies, Investment Fund Category | The investment strategy supports the objective of the funds, which is to preserve capital, maintain sufficient liquidity and earn a consistent rate of return. | ||||
| Health care cost trend (in hundredths) | 6.80% | 7.00% | |||
| Health care cost rate declining through | 2025 | ||||
| Ultimate cost trend rate (in hundredths) | 4.50% | 4.50% | |||
| Effect on total service and interest component, increase | $ 0.9 | ||||
| Effect on total service and interest component, decrease | (1.1) | ||||
| Effect on post-retirement benefit obligation, increase | 4.0 | ||||
| Effect on post-retirement benefit obligation, decrease | $ (3.6) | ||||
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| X | ||||||||||
- Definition -- None. No documentation exists for this element. -- No definition available.
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| X | ||||||||||
- Definition The pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income or regulatory (assets) liabilities as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets. No definition available.
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| X | ||||||||||
- Definition Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost. No definition available.
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| X | ||||||||||
- Definition Of the original amount of transition assets as of the date FAS 87 or 106 was initially applied, the portion of which has yet to be recognized as components of net periodic benefit cost. This amount is pretax. No definition available.
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| X | ||||||||||
- Definition Amount related to other amounts recorded in accumulated other comprehensive income or regulatory (assets) liabilities, before tax. No definition available.
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| X | ||||||||||
- Definition The aggregate amount recognized in accumulated other comprehensive income, regulatory assets and regulatory liabilities associated with the defined benefit plan(s). No definition available.
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| X | ||||||||||
- Definition The aggregate net amount recognized in the balance sheet associated with the defined benefit plan(s) before OCI/regulatory treatment. No definition available.
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| X | ||||||||||
- Definition The amount of payments paid from plan assets for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets. No definition available.
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| X | ||||||||||
- Definition The increase in the fair value of plan assets from contributions made by the employer and plan participants. No definition available.
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| X | ||||||||||
- Definition Amount included in accumulated other comprehensive income (AOCI) or a regulatory asset related to gain (loss) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position. No definition available.
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| X | ||||||||||
- Definition Amount included in accumulated other comprehensive income (AOCI) or a regulatory asset related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position. No definition available.
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| X | ||||||||||
- Definition Increase (decrease) in net periodic benefit costs related to regulatory adjustments. No definition available.
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| X | ||||||||||
- Definition The length of time for amortization of net actuarial gains and losses for financial reporting purposes. No definition available.
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| X | ||||||||||
- Definition The length of time for amortization of net actuarial gains and losses for regulatory reporting purposes. No definition available.
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| X | ||||||||||
- Definition The total amount of net periodic benefit cost for defined benefit plans for the period before regulatory adjustment. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. No definition available.
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| X | ||||||||||
- Definition -- None. No documentation exists for this element. -- No definition available.
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| X | ||||||||||
- Definition Amount before tax of reclassification adjustment from accumulated other comprehensive (income) loss or regulatory asset/liability for prior service cost (credit) related to pension and other postretirement benefit plans. No definition available.
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| X | ||||||||||
- Definition Changes in pension and postretirement benefit plan assets and benefit obligations recognized in OCI or regulatory assets/liabilities due to other regulatory activity. No definition available.
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| X | ||||||||||
- Definition Amount before tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit. No definition available.
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| X | ||||||||||
- Definition Amount before tax of reclassification adjustment from accumulated other comprehensive income (loss) or regulatory asset/liability related to pension and other postretirement benefit plans. No definition available.
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| X | ||||||||||
- Definition Amount before tax of reclassification adjustment from accumulated other comprehensive income (loss) or regulatory asset/liability for net transition asset (obligation) related to pension and other postretirement benefit plans. No definition available.
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| X | ||||||||||
- Definition Amount before tax of cost (credit) of benefit changes attributable to plan participants' prior service resulting from a plan amendment or plan initiation that has not been recognized in net periodic benefit costs (credit). No definition available.
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| X | ||||||||||
- Definition Assets that have been segregated to cover the unfunded GMO SERP acquired in the GMO acquisition. No definition available.
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| X | ||||||||||
- Definition Total recognized in net periodic benefit costs and other comprehensive income or regulatory asset/liability. No definition available.
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| X | ||||||||||
- Definition The total recognized in other comprehensive income or regulatory assets/liabilities. No definition available.
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| X | ||||||||||
- Definition The unfunded accumulated benefit obligation related to the GMO SERP acquired in the GMO acquisition. No definition available.
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| X | ||||||||||
- Definition For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of gains or losses recognized in net periodic benefit cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of the transition obligation or asset recognized in net periodic benefit cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The aggregate net amount recognized in the balance sheet associated with the defined benefit plan(s). Will normally be the same as the Defined Benefit Plan, Funded Status of Plan, Total. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The amount for overfunded plans recognized in the balance sheet as a noncurrent asset associated with a defined benefit pension plan or other postretirement defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The interest rate used to adjust for the time value of money for the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Expected rate of compensation increases (for pay-related plans). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The interest rate used to adjust for the time value of money. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Expected rate of compensation increases (for pay-related plans). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Description and explanation of the assumptions (including assumed discount rates, rates of compensation increase, and expected long-term rates of return on plan assets) used to calculate the benefit obligation and the assumptions used to calculate net periodic benefit cost. May also include other assumptions such as market-related value, average remaining service period, and average remaining life expectancy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition 1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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| X | ||||||||||
- Definition The amount of contributions made by plan participants. This item represents a periodic increase to the plan obligation and an increase to plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of benefits from a defined benefit plan expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of benefits from a defined benefit plan expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of benefits from a defined benefit plan expected to be paid in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of benefits from a defined benefit plan expected to be paid in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of benefits from a defined benefit plan expected to be paid in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition A description of the investment strategies for any investment fund investments by the Plan which are considered and disclosed as a major investment category by the Plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition If aggregate disclosures are presented, the aggregate benefit obligation for plans with benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition If aggregate disclosures are presented, the aggregate fair value of plan assets for plans with benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of net gain (loss) recognized in net periodic benefit cost as a result of an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include, but are not limited to, lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contracts to cover vested benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of decrease that relates to an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount that relates to an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Description of target allocation percentages, or range of percentages, considering the major categories of plan assets as of the latest statement of financial position presented (on a weighted-average basis for employers with more than one plan) that are pertinent to an understanding of the plan investment policies and strategies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The ultimate trend rate for health care costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Year the ultimate health care cost trend rate is expected to be reached, in CCYY format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The amount of the cost recognized during the period for defined contribution plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition For a classified balance sheet, the amount recognized in balance sheet as a current liability associated with an underfunded defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement defined benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Pension Plans and Other Employee Benefits Pension Plans Fair Value (Details) - USD ($) |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pension Plans, Defined Benefit [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | $ 723,900,000 | $ 730,000,000 | $ 703,000,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 171,800,000 | 175,200,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Real Estate [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [1] | 45,900,000 | 38,900,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [1] | 33,700,000 | 31,200,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Real Estate [Member] | Institutional Common Collective Trust Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 33,700,000 | 31,200,000 | [1] | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Real Estate [Member] | Real Estate Investment Trust [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 12,200,000 | 7,700,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Hedge Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [2] | 23,700,000 | 24,100,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [2] | 23,700,000 | 24,100,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [3] | 226,000,000 | 235,200,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 30,500,000 | 31,600,000 | [3] | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US Equity Securities [Member] | Traded Mutual Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 121,600,000 | 78,100,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US Equity Securities [Member] | Institutional Common Collective Trust Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 30,500,000 | 31,600,000 | [3] | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US Equity Securities [Member] | Common Stock and Exchange Traded Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 73,900,000 | 125,500,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | International Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [4] | 147,400,000 | 147,300,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [4] | 37,700,000 | 38,600,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | International Equity Securities [Member] | Traded Mutual Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 34,200,000 | 38,600,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | International Equity Securities [Member] | Institutional Common Collective Trust Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [4] | 37,700,000 | 38,600,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | International Equity Securities [Member] | American Depository Receipts Global Depository Receipts and Ordinary Shares [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 75,500,000 | 70,100,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Commodity Contract [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [5] | 5,800,000 | 5,900,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [5] | 5,800,000 | 5,900,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [6] | 60,400,000 | 66,100,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [6] | 40,400,000 | 43,800,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Traded Mutual Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 20,000,000 | 22,300,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Institutional Common Collective Trust Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 40,400,000 | 43,800,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 48,800,000 | 44,200,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 19,000,000 | 21,000,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [7] | 108,800,000 | 109,000,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [7] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US corporate bonds [Member] | Corporate Bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 103,000,000 | 100,300,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US corporate bonds [Member] | Collateralized Mortgage Obligation Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 2,900,000 | 4,000,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | US corporate bonds [Member] | Asset-backed Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 2,900,000 | 4,700,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 10,200,000 | 13,600,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 26,000,000 | 16,700,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 1,900,000 | 8,000,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 412,200,000 | 402,900,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Real Estate [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [1] | 12,200,000 | 7,700,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Hedge Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [2] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [3] | 195,500,000 | 203,600,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | International Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [4] | 109,700,000 | 108,400,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Commodity Contract [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [5] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [6] | 20,000,000 | 22,300,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 48,800,000 | 44,200,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [7] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 26,000,000 | 16,700,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 139,900,000 | 151,900,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Real Estate [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [1] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Hedge Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [2] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [3] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | International Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [4] | 0 | 300,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Commodity Contract [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [5] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [6] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 19,000,000 | 21,000,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [7] | 108,800,000 | 109,000,000 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 10,200,000 | 13,600,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 1,900,000 | 8,000,000 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Real Estate [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [1] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Hedge Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [2] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [3] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | International Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [4] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Commodity Contract [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [5] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [6] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [7] | 0 | 0 | ||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 114,300,000 | 110,600,000 | $ 101,200,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 68,800,000 | 72,800,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 3,200,000 | 3,200,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [8] | 68,900,000 | 73,000,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [8] | 68,800,000 | 72,800,000 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Traded Mutual Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 100,000 | 200,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Institutional Common Collective Trust Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [8] | 68,800,000 | 72,800,000 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 3,900,000 | 2,700,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 5,400,000 | 4,900,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [9] | 15,600,000 | 13,000,000 | ||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | [9] | 0 | 0 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | US corporate bonds [Member] | Corporate Bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 12,600,000 | 10,300,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | US corporate bonds [Member] | Collateralized Mortgage Obligation Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 600,000 | 800,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | US corporate bonds [Member] | Asset-backed Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 2,400,000 | 1,900,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 1,600,000 | 1,500,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 14,000,000 | 10,400,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 1,700,000 | 1,900,000 | |||||||||||||||||||||
| Alternative Investments, Fair Value Disclosure | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 21,200,000 | 16,500,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 3,200,000 | 3,200,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [8] | 100,000 | 200,000 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 3,900,000 | 2,700,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [9] | 0 | 0 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 14,000,000 | 10,400,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 24,300,000 | 21,300,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [8] | 0 | 0 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 5,400,000 | 4,900,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [9] | 15,600,000 | 13,000,000 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 1,600,000 | 1,500,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 1,700,000 | 1,900,000 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [8] | 0 | 0 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US Agency, State and Political Subdivisions Debt Securities [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | US corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | [9] | 0 | 0 | ||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign corporate bonds [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | 0 | 0 | |||||||||||||||||||||
| Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Other Plan Investments [Member] | |||||||||||||||||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||||||||||||||||
| Fair Value, Plan Assets | $ 0 | $ 0 | |||||||||||||||||||||
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- Definition Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Equity Compensation (Details) - USD ($) $ / shares in Units, $ in Millions |
12 Months Ended | |||||
|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
| Maximum number of shares of common shares authorized (in shares) | 8,000,000 | |||||
| Equity compensation expense | $ 4.0 | $ 9.9 | $ 5.6 | |||
| Income tax benefit | $ 1.4 | $ 3.6 | $ 1.9 | |||
| Performance Shares [Member] | ||||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
| Expected volatility, minimum (in hundredths) | 16.00% | |||||
| Expected volatility, maximum (in hundredths) | 17.00% | |||||
| Expected dividend yield range (in hundredths) | 3.72%-4.03% | |||||
| Risk-free interest rate, minimum (in hundredths) | 0.86% | |||||
| Risk-free interest rate, maximum (in hundredths) | 1.02% | |||||
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | ||||||
| Beginning balance (in shares) | 534,016 | |||||
| Granted (in shares) | 232,838 | |||||
| Earned (in shares) | (25,844) | |||||
| Performance adjustment (in shares) | (77,515) | |||||
| Forfeited (in shares) | (54,485) | |||||
| Ending balance (in shares) | 609,010 | 534,016 | ||||
| Weighted average beginning balance (in dollars per share) | [1] | $ 25.11 | ||||
| Weighted average granted (in dollars per share) | [1] | 24.03 | $ 28.78 | $ 24.17 | ||
| Weighted average earned (in dollars per share) | [1] | 19.48 | ||||
| Weighted average forfeited (in dollars per share) | [1] | 25.68 | ||||
| Weighted average performance adjustment (in dollars per share) | [1] | 19.48 | ||||
| Weighted average ending balance (in dollars per share) | [1] | $ 25.60 | $ 25.11 | |||
| Total unrecognized compensation expense | $ 5.9 | |||||
| Remaining weighted-average contractual term (in years) | 1 year | |||||
| Fair value of performance shares earned and paid | $ 0.5 | $ 2.8 | $ 2.4 | |||
| Restricted Stock [Member] | ||||||
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | ||||||
| Beginning balance (in shares) | 267,390 | |||||
| Granted (in shares) | 92,780 | |||||
| Vested (in shares) | (110,496) | |||||
| Forfeited (in shares) | (18,166) | |||||
| Ending balance (in shares) | 231,508 | 267,390 | ||||
| Weighted average beginning balance (in dollars per share) | [1] | $ 22.31 | ||||
| Weighted average granted (in dollars per share) | [1] | 25.89 | $ 25.70 | $ 22.47 | ||
| Weighted average vested (in dollars per share) | [1] | 19.71 | ||||
| Weighted average forfeited (in dollars per share) | [1] | 24.81 | ||||
| Weighted average ending balance (in dollars per share) | [1] | $ 24.78 | $ 22.31 | |||
| Total unrecognized compensation expense | $ 2.4 | |||||
| Total fair value of shares vested | $ 2.2 | $ 1.9 | $ 1.2 | |||
| Remaining weighted-average contractual term (in years) | 1 year 3 months | |||||
| Kansas City Power and Light Company [Member] | ||||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
| Equity compensation expense | $ 2.6 | 6.9 | 4.0 | |||
| Income tax benefit | $ 0.9 | $ 2.4 | $ 1.3 | |||
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were earned during the reporting period. No definition available.
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- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee earned the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. No definition available.
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were adjusted during the reporting period based on performance criteria. No definition available.
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- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were adjusted during the reporting period based on performance criteria. No definition available.
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Unrecognized cost of unvested share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. No definition available.
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- Definition The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. No definition available.
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Equity Compensation Equity Compensation Deferred Directors (Details) - Director [Member] - Director Deferred Share Units [Member] |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2015
$ / shares
shares
| ||||
| Director deferred share units [Roll Forward] | ||||
| Director deferred share units, beginning balance (in shares) | shares | 110,741 | |||
| Director deferred share units, issued (in shares) | shares | 24,576 | |||
| Director deferred share units, converted (in shares) | shares | (19,902) | |||
| Director deferred share units, ending balance (in shares) | shares | 115,415 | |||
| Weighted-average grant date fair value, director deferred share units, beginning balance (in dollars per share) | $ / shares | $ 21.98 | [1] | ||
| Weighted-average grant date fair value, director deferred share units, issued (in dollars per share) | $ / shares | 26.15 | [1] | ||
| Weighted average grant date fair value director deferred share units, converted | $ / shares | 21.50 | [1] | ||
| Weighted-average grant date fair value, director deferred share units, ending balance (in dollars per share) | $ / shares | $ 22.95 | [1] | ||
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Short-term Borrowings and Short-term Bank Lines of Credit (Details) - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Short-term Debt [Line Items] | ||
| Amount of outstanding cash borrowings | $ 10,000,000 | $ 4,000,000 |
| Commercial paper outstanding | 224,000,000 | 358,300,000 |
| Parent Company [Member] | ||
| Short-term Debt [Line Items] | ||
| Amount of outstanding cash borrowings | 10,000,000 | 4,000,000 |
| Parent Company [Member] | Revolving Credit Facility [Member] | ||
| Short-term Debt [Line Items] | ||
| Amount of revolving credit facility | $ 200,000,000 | |
| Revolving credit facility expiration date | Oct. 31, 2019 | |
| Maximum borrowing capacity with transfer of unused commitments | $ 400,000,000 | |
| Line of Credit Facility, Covenant Terms | A default by Great Plains Energy or any of its significant subsidiaries on other indebtedness totaling more than $50.0 million is a default under the facility. Under the terms of this facility, Great Plains Energy is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the facility, not greater than 0.65 to 1.00 at all times. | |
| Line of Credit Facility, Covenant Compliance | in compliance | |
| Amount of outstanding cash borrowings | $ 10,000,000 | $ 4,000,000 |
| Weighted-average interest rate from outstanding borrowings | 1.94% | 1.69% |
| Amount of letters of credit outstanding | $ 200,000 | $ 0 |
| Kansas City Power and Light Company [Member] | ||
| Short-term Debt [Line Items] | ||
| Commercial paper outstanding | $ 180,300,000 | $ 358,300,000 |
| Weighted-average interest rate from outstanding borrowings | 0.70% | 0.48% |
| Kansas City Power and Light Company [Member] | Revolving Credit Facility [Member] | ||
| Short-term Debt [Line Items] | ||
| Amount of revolving credit facility | $ 600,000,000 | |
| Revolving credit facility expiration date | Oct. 31, 2019 | |
| Maximum transfer of unused commitments | $ 200,000,000 | |
| Line of Credit Facility, Covenant Terms | A default by KCP&L on other indebtedness totaling more than $50.0 million is a default under the facility. Under the terms of this facility, KCP&L is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the facility, not greater than 0.65 to 1.00 at all times. | |
| Line of Credit Facility, Covenant Compliance | in compliance | |
| Amount of outstanding cash borrowings | $ 0 | $ 0 |
| Amount of letters of credit outstanding | 2,700,000 | 2,700,000 |
| KCPL Greater Missouri Operations [Member] | ||
| Short-term Debt [Line Items] | ||
| Commercial paper outstanding | $ 43,700,000 | 0 |
| Weighted-average interest rate from outstanding borrowings | 0.65% | |
| KCPL Greater Missouri Operations [Member] | Revolving Credit Facility [Member] | ||
| Short-term Debt [Line Items] | ||
| Amount of revolving credit facility | $ 450,000,000 | |
| Revolving credit facility expiration date | Oct. 31, 2019 | |
| Maximum transfer of unused commitments | $ 200,000,000 | |
| Line of Credit Facility, Covenant Terms | A default by GMO or any of its significant subsidiaries on other indebtedness totaling more than $50.0 million is a default under the facility. Under the terms of this facility, GMO is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the facility, not greater than 0.65 to 1.00 at all times. | |
| Line of Credit Facility, Covenant Compliance | in compliance | |
| Amount of outstanding cash borrowings | $ 0 | 0 |
| Amount of letters of credit outstanding | $ 2,500,000 | $ 3,200,000 |
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- Definition The maximum amount of lending capacity under Great Plains Energy's credit facility if unused commitments are transferred between that credit facility and the credit facilities of KCPL and GMO No definition available.
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| X | ||||||||||
- Definition The maximum amount of unused commitments that can be transferred between the entity's revolving credit facility and Great Plains Energy's revolving credit facility. No definition available.
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- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. No definition available.
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- Definition Identification of whether the entity has been in compliance with any credit facility debt covenants during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Description of the conditions for borrowing under the credit facility including the nature of any restrictions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Date the credit facility terminates, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Carrying amount at the balance sheet date of borrowings from a bank, not elsewhere enumerated in the taxonomy, with a maturity within one year (or within one operating cycle if longer) from the date of borrowing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Weighted average interest rate of short-term debt outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Long-Term Debt (Details) - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2015 |
Aug. 31, 2015 |
Mar. 31, 2015 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
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| Debt Instrument [Line Items] | |||||||||||||||
| Current maturities | $ (1.1) | $ (15.1) | |||||||||||||
| Long-term debt excluding current maturities | [1] | 3,745.1 | 3,465.7 | ||||||||||||
| Amortization of Financing Costs | 4.1 | 4.8 | $ 5.7 | ||||||||||||
| Repayments of Long-term Debt | 87.0 | 13.4 | 265.3 | ||||||||||||
| Long-term Debt, Fiscal Year Maturity [Abstract] | |||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months | 1.1 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Two | 382.1 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Three | 351.1 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Four | 401.1 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Five | 1.1 | ||||||||||||||
| Kansas City Power and Light Company [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Current maturities | 0.0 | (14.0) | |||||||||||||
| Unamortized discount and premium, net and debt issuance costs | (17.3) | (19.5) | |||||||||||||
| Long-term debt excluding current maturities | [1] | 2,563.1 | 2,282.8 | ||||||||||||
| Amortization of Financing Costs | 3.0 | 3.0 | 3.2 | ||||||||||||
| Repayments of Long-term Debt | 85.9 | 0.0 | 2.6 | ||||||||||||
| Long-term Debt, Fiscal Year Maturity [Abstract] | |||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months | 0.0 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Two | 281.0 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Three | 350.0 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Four | 400.0 | ||||||||||||||
| Long-term Debt, Maturities, Repayments of Principal in Year Five | 0.0 | ||||||||||||||
| Kansas City Power and Light Company [Member] | Secured Debt [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | 510.5 | 596.4 | |||||||||||||
| Kansas City Power and Light Company [Member] | Secured Debt [Member] | General Mortgage Bonds EIRR due 2017-2035 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [2] | 110.5 | 146.4 | ||||||||||||
| EIRR bonds repurchased and held | $ 21.9 | ||||||||||||||
| Debt Instrument Maturity Date Range End | Dec. 31, 2035 | ||||||||||||||
| Debt Instrument Maturity Date Range Start | Dec. 31, 2017 | ||||||||||||||
| Long-term Debt, Weighted Average Interest Rate | 2.47% | ||||||||||||||
| Bonds purchased in lieu of redemption | $ 21.9 | ||||||||||||||
| KCPL Municipal Bond Insurance Policies [Abstract] | |||||||||||||||
| Principal outstanding covered by insurance policies | $ 21.9 | ||||||||||||||
| Insurance Agreement Covenant Description | The insurance agreements contain a covenant that the indebtedness to total capitalization ratio of KCP&L and its consolidated subsidiaries will not be greater than 0.68 to 1.00. | ||||||||||||||
| Insurance Agreement Covenant Compliance | in compliance | ||||||||||||||
| Insurance Agreement Covenant Indebtedness To Total Capitalization Ratio Maximum | 75.00% | ||||||||||||||
| Proportion Of Secured Debt To Total Indebtedness Based On Bond Ratings Maximum In Hundredths | 50.00% | ||||||||||||||
| Aggregate Amount Of Outstanding General Mortgage Bonds As Percentage Of Total Capitalization Maximum In Hundredths | 10.00% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Secured Debt [Member] | General Mortgage bonds Series 2009A due 2019 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [3] | $ 400.0 | 400.0 | ||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2019 | ||||||||||||||
| Interest rates (in hundredths) | 7.15% | ||||||||||||||
| Rate after amortizing gains or losses in Other Comprehensive Income (in hundredths) | 8.59% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Secured Debt [Member] | General Mortgage bonds EIRR series 2005 due 2035 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 0.0 | 50.0 | |||||||||||||
| EIRR bonds repurchased and held | $ 50.0 | ||||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2035 | ||||||||||||||
| Interest rates (in hundredths) | 4.65% | ||||||||||||||
| Bonds purchased in lieu of redemption | $ 50.0 | ||||||||||||||
| KCPL Municipal Bond Insurance Policies [Abstract] | |||||||||||||||
| Principal outstanding covered by insurance policies | $ 50.0 | ||||||||||||||
| Insurance Agreement Covenant Description | The insurance agreements contain a covenant that the indebtedness to total capitalization ratio of KCP&L and its consolidated subsidiaries will not be greater than 0.68 to 1.00. | ||||||||||||||
| Insurance Agreement Covenant Compliance | in compliance | ||||||||||||||
| Insurance Agreement Covenant Indebtedness To Total Capitalization Ratio Maximum | 75.00% | ||||||||||||||
| Proportion Of Secured Debt To Total Indebtedness Based On Bond Ratings Maximum In Hundredths | 50.00% | ||||||||||||||
| Aggregate Amount Of Outstanding General Mortgage Bonds As Percentage Of Total Capitalization Maximum In Hundredths | 10.00% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Secured Debt [Member] | Secured EIRR Bonds Series 2005 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Repayments of Long-term Debt | $ 14.0 | ||||||||||||||
| Kansas City Power and Light Company [Member] | Senior Notes [Member] | Senior notes due 2017 KCPL [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [3] | $ 250.0 | 250.0 | ||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2017 | ||||||||||||||
| Interest rates (in hundredths) | 5.85% | ||||||||||||||
| Rate after amortizing gains or losses in Other Comprehensive Income (in hundredths) | 5.72% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Senior Notes [Member] | Senior notes due 2018 KCPL [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [3] | $ 350.0 | 350.0 | ||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2018 | ||||||||||||||
| Interest rates (in hundredths) | 6.375% | ||||||||||||||
| Rate after amortizing gains or losses in Other Comprehensive Income (in hundredths) | 7.49% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Senior Notes [Member] | Senior Notes due 2023 KCPL [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 300.0 | 300.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2023 | ||||||||||||||
| Interest rates (in hundredths) | 3.15% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Senior Notes [Member] | Senior Notes due 2025 KCPL [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 350.0 | 0.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2025 | ||||||||||||||
| Interest rates (in hundredths) | 3.65% | ||||||||||||||
| Proceeds from Issuance of Senior Long-term Debt | $ 350.0 | ||||||||||||||
| Kansas City Power and Light Company [Member] | Senior Notes [Member] | Senior notes due 2035 KCPL [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [3] | $ 250.0 | 250.0 | ||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2035 | ||||||||||||||
| Interest rates (in hundredths) | 6.05% | ||||||||||||||
| Rate after amortizing gains or losses in Other Comprehensive Income (in hundredths) | 5.78% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Senior Notes [Member] | Senior Notes Due 2041 KCPL [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 400.0 | 400.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2041 | ||||||||||||||
| Interest rates (in hundredths) | 5.30% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Unsecured Debt [Member] | EIRR Bonds Series 2007A and 2007B due 2035 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [4] | $ 146.5 | 146.5 | ||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2035 | ||||||||||||||
| Variable rate (in hundredths) | 0.01% | ||||||||||||||
| Kansas City Power and Light Company [Member] | Unsecured Debt [Member] | EIRR bonds 2.875 percent Series 2008 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 23.4 | 23.4 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2038 | ||||||||||||||
| Interest rates (in hundredths) | 2.875% | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Secured Debt [Member] | First Mortgage Bonds due through 2021 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 6.8 | 7.9 | |||||||||||||
| Debt Instrument Maturity Date Range End | Dec. 31, 2021 | ||||||||||||||
| Debt Instrument Maturity Date Range Start | Dec. 31, 2016 | ||||||||||||||
| Interest rates (in hundredths) | 9.44% | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Senior Notes [Member] | Senior notes 8.27 percent series due 2021 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 80.9 | 80.9 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2021 | ||||||||||||||
| Interest rates (in hundredths) | 8.27% | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Senior Notes [Member] | Senior Notes Series A due 2025 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 125.0 | 125.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2025 | ||||||||||||||
| Interest rates (in hundredths) | 3.49% | ||||||||||||||
| GMO Senior Notes [Abstract] | |||||||||||||||
| Debt Instrument, Covenant Description | Under the terms of the note purchase agreement for GMO's Series A, B and C Senior Notes, GMO is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the agreement, not greater than 0.65 to 1.00 at all times. In addition, GMO's priority debt, as defined in the agreement, cannot exceed 15% of consolidated tangible net worth, as defined in the agreement. | ||||||||||||||
| Debt Instrument, Covenant Compliance | in compliance | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Senior Notes [Member] | Senior Notes Series B due 2033 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 75.0 | 75.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2033 | ||||||||||||||
| Interest rates (in hundredths) | 4.06% | ||||||||||||||
| GMO Senior Notes [Abstract] | |||||||||||||||
| Debt Instrument, Covenant Description | GMO is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the agreement, not greater than 0.65 to 1.00 at all times. In addition, GMO's priority debt, as defined in the agreement, cannot exceed 15% of consolidated tangible net worth, as defined in the agreement. | ||||||||||||||
| Debt Instrument, Covenant Compliance | in compliance | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Senior Notes [Member] | Senior Notes Series C due 2043 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 150.0 | 150.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2043 | ||||||||||||||
| Interest rates (in hundredths) | 4.74% | ||||||||||||||
| GMO Senior Notes [Abstract] | |||||||||||||||
| Debt Instrument, Covenant Description | GMO is required to maintain a consolidated indebtedness to consolidated capitalization ratio, as defined in the agreement, not greater than 0.65 to 1.00 at all times. In addition, GMO's priority debt, as defined in the agreement, cannot exceed 15% of consolidated tangible net worth, as defined in the agreement. | ||||||||||||||
| Debt Instrument, Covenant Compliance | in compliance | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Medium-term Notes [Member] | Medium term notes 7.33 percent series due 2023 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 3.0 | 3.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2023 | ||||||||||||||
| Interest rates (in hundredths) | 7.33% | ||||||||||||||
| KCPL Greater Missouri Operations [Member] | Medium-term Notes [Member] | Medium term notes 7.17 percent series due 2023 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 7.0 | 7.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2023 | ||||||||||||||
| Interest rates (in hundredths) | 7.17% | ||||||||||||||
| Parent Company [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Long-term debt excluding current maturities | $ 738.1 | 738.0 | |||||||||||||
| Repayments of Long-term Debt | 0.0 | 0.0 | 250.0 | ||||||||||||
| Parent Company [Member] | Senior Notes [Member] | Senior notes due 2017 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | [3] | $ 100.0 | 100.0 | ||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2017 | ||||||||||||||
| Interest rates (in hundredths) | 6.875% | ||||||||||||||
| Rate after amortizing gains or losses in Other Comprehensive Income (in hundredths) | 7.33% | ||||||||||||||
| Parent Company [Member] | Senior Notes [Member] | Senior Notes Due 2021 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 350.0 | 350.0 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2021 | ||||||||||||||
| Interest rates (in hundredths) | 4.85% | ||||||||||||||
| Parent Company [Member] | Senior Notes [Member] | Senior Notes Due 2022 [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Principal outstanding | $ 287.5 | 287.5 | |||||||||||||
| Debt Instrument, Maturity Date | Dec. 31, 2022 | ||||||||||||||
| Interest rates (in hundredths) | 5.292% | ||||||||||||||
| Other Consolidated Entities [Member] | |||||||||||||||
| Debt Instrument [Line Items] | |||||||||||||||
| Current maturities | $ (1.1) | (1.1) | |||||||||||||
| Unamortized discount and premium, net and debt issuance costs | (2.1) | (2.3) | |||||||||||||
| Amortization of Financing Costs | $ 1.1 | $ 1.8 | $ 2.5 | ||||||||||||
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| X | ||||||||||
- Definition If the aggregate amount of outstanding general mortgage bonds as a percentage of total capitalization exceeds this amount, additional collateral must be provided to the insurance company under the municipal bonds insurance agreement. No definition available.
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- Definition Environmental Improvement Revenue Refunding bonds that were purchased rather than remarketed by KCP&L No definition available.
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- Definition Amount of long-term debt before deduction of unamortized discount or premium that has been repurchased and is being held by the issuer. No definition available.
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- Definition Debt instrument unamortized discount premium and debt issuance costs,net No definition available.
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- Definition GMO Senior Notes No definition available.
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- Definition States whether the entity was in compliance with the municipal bond insurance covenants throughout the reporting period, and describes facts and circumstances of any compliance failure. No definition available.
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- Definition Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the municipal bond insurance policy. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants. No definition available.
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- Definition The maximum indebtedness to total capitalization ratio permitted under the municipal bond insurance policy. No definition available.
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- Definition KCPL Municipal Bond Insurance Policies [Abstract] No definition available.
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- Definition Principal value of debt instrument outstanding which is covered by a municipal bond insurance policy between KCP and L and Syncora Guarantee, Inc. (Syncora). The insurance agreements beotween KCP and L and Syncora provide for reimbursement by KCP and L for any amounts that Syncora pays under the municipal bond insurance policies. No definition available.
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- Definition The maximum proportion of secured debt to total capitalization under which KCP and L may issue additional bonds per its General Mortgage Indenture, if the long-term rating for such bonds by Standard and Poor's or Moody's Investors Service would be at or below A- or A3. If this ratio of secured debt to total capitalization would exceed this amount after giving effect to such additional bonds, no additional bonds may be issued. No definition available.
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- Definition Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition States whether the entity was in compliance with the debt covenants throughout the reporting period, and describes facts and circumstances of any compliance failure. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the debt agreement. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average interest rate of long-term debt outstanding. No definition available.
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- Definition The cash inflow from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Common Shareholders' Equity (Details) shares in Millions, $ in Billions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
shares
| |
| Common Shareholders' Equity [Line Items] | |
| Shares authorized under the Dividend Reinvestment and Direct Stock Purchase Plan (in shares) | 7.0 |
| Number of shares available for grant under the Dividend Reinvestment and Direct Stock Purchase Plan (in shares) | 2.1 |
| Shares registered under the defined contribution savings plan (in shares) | 14.3 |
| Number of shares available under the defined contribution savings plan (in shares) | 1.0 |
| Restrictions on the payment of common stock dividends | Great Plains Energy's articles of incorporation restrict the payment of common stock dividends in the event common equity is 25% or less of total capitalization. In addition, if preferred stock dividends are not declared and paid when scheduled, Great Plains Energy could not declare or pay common stock dividends or purchase any common shares. If the unpaid preferred stock dividends equal four or more full quarterly dividends, the preferred shareholders, voting as a single class, could elect the smallest number of directors necessary to constitute a majority of the full Board. Certain conditions in the MPSC and KCC orders authorizing the holding company structure require Great Plains Energy and KCP&L to maintain consolidated common equity of at least 30% and 35%, respectively, of total capitalization (including only the amount of short-term debt in excess of the amount of construction work in progress). Under the Federal Power Act, KCP&L and GMO generally can pay dividends only out of retained earnings. The revolving credit agreements of Great Plains Energy, KCP&L and GMO and the note purchase agreement for GMO's Series A, B and C Senior Notes contain a covenant requiring the respective company to maintain a consolidated indebtedness to consolidated total capitalization ratio of not more than 0.65 to 1.00 at all times. |
| Restricted net assets of subsidiaries | $ | $ 2.8 |
| X | ||||||||||
- Definition Common Shareholders' Equity [Line Items] No definition available.
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| X | ||||||||||
- Definition The difference between the maximum number of shares authorized for issuance under the defined contribution plan (including the effects of amendments and adjustments), and the number of shares already issued. No definition available.
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| X | ||||||||||
- Definition The number of shares registered with the Securities and Exchange Commission for the defined contribution savings plan. No definition available.
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| X | ||||||||||
- Definition The difference between the maximum number of shares registered for issuance under the Dividend Reinvestment and Direct Stock Purchase Plan (including the effects of amendments and adjustments), and the number of shares already issued. No definition available.
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| X | ||||||||||
- Definition The number of shares registered with the Securities and Exchange Commission for the Dividend Reinvestment and Direct Stock Purchase Plan. No definition available.
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| X | ||||||||||
- Definition Amount of restricted net assets of consolidated and unconsolidated subsidiaries as of the end of the most recently completed fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Statement regarding other restrictions (not covered by a more specific disclosure element) on the entity's ability to pay dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Class of Stock [Line Items] | ||
| Preferred Stock, Value, Issued | $ 39.0 | $ 39.0 |
| No Par Preference Stock [Member] | ||
| Class of Stock [Line Items] | ||
| Preferred Stock, Shares Authorized | 11,000,000 | |
| Cumulative Preferred Stock [Member] | ||
| Class of Stock [Line Items] | ||
| Preferred Stock, Shares Authorized | 390,000 | |
| Preferred Stock, Shares Outstanding | 390,000 | |
| Preferred Stock, Value, Issued | $ 39.0 | |
| Preferred Stock, Par or Stated Value Per Share | $ 100 | |
| Cumulative No Par Preferred Stock [Member] | ||
| Class of Stock [Line Items] | ||
| Preferred Stock, Shares Authorized | 1,600,000 | |
| Minimum [Member] | Cumulative Preferred Stock [Member] | ||
| Class of Stock [Line Items] | ||
| Optional Redemption Percentage of Par Value | 101.00% | |
| Maximum [Member] | Cumulative Preferred Stock [Member] | ||
| Class of Stock [Line Items] | ||
| Optional Redemption Percentage of Par Value | 103.70% |
| X | ||||||||||
- Definition The percentage of par value at which the preferred stock may be redeemed at the option of the Company. No definition available.
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Commitments and Contingencies Commitments and Contingencies Contractual Commitments (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Lease Expense [Abstract] | |||
| Lease expense | $ 16.8 | $ 16.0 | $ 18.5 |
| Operating Leases [Abstract] | |||
| Operating Leases, Future Minimum Payments Due, Next Twelve Months | 12.3 | ||
| Operating Leases, Future Minimum Payments, Due in Two Years | 10.6 | ||
| Operating Leases, Future Minimum Payments, Due in Three Years | 9.7 | ||
| Operating Leases, Future Minimum Payments, Due in Four Years | 9.9 | ||
| Operating Leases, Future Minimum Payments, Due in Five Years | 9.6 | ||
| Operating Leases, Future Minimum Payments, Due Thereafter | 121.5 | ||
| Operating Leases, Future Minimum Payments Due, Total | 173.6 | ||
| Capital Leases [Abstract] | |||
| Capital Leases, Future Minimum Payments Due, Next Twelve Months | 0.4 | ||
| Capital Leases, Future Minimum Payments Due in Two Years | 0.4 | ||
| Capital Leases, Future Minimum Payments Due in Three Years | 0.4 | ||
| Capital Leases, Future Minimum Payments Due in Four Years | 0.4 | ||
| Capital Leases, Future Minimum Payments Due in Five Years | 0.4 | ||
| Capital Leases, Future Minimum Payments Due Thereafter | 3.5 | ||
| Capital Leases, Future Minimum Payments Due, Total | 5.5 | ||
| Total Commitments [Abstract] | |||
| Total Commitments, Due in Next Twelve Months | 450.8 | ||
| Total Commitments, Due within Two Years | 353.4 | ||
| Total Commitments, Due within Three Years | 297.9 | ||
| Total Commitments, Due within Four Years | 294.5 | ||
| Total Commitments, Due within Five Years | 252.8 | ||
| Total Commitments, Due Thereafter | 728.1 | ||
| Total Commitments Due | 2,377.5 | ||
| Public Utilities, Inventory, Fuel [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 311.4 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 283.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 212.7 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 196.9 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 190.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 52.5 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 1,247.0 | ||
| Purchased Power [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 47.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 47.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 47.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 47.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 47.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 509.5 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 746.0 | ||
| Capacity [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 1.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 1.2 | ||
| Non-regulated natural gas transportation [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 3.5 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 0.9 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 4.4 | ||
| Other purchase commitments [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 74.7 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 11.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 27.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 40.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 5.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 41.1 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 199.8 | ||
| Kansas City Power and Light Company [Member] | |||
| Lease Expense [Abstract] | |||
| Lease expense | 15.0 | $ 14.0 | $ 16.0 |
| Operating Leases [Abstract] | |||
| Operating Leases, Future Minimum Payments Due, Next Twelve Months | 11.9 | ||
| Operating Leases, Future Minimum Payments, Due in Two Years | 10.6 | ||
| Operating Leases, Future Minimum Payments, Due in Three Years | 9.7 | ||
| Operating Leases, Future Minimum Payments, Due in Four Years | 9.9 | ||
| Operating Leases, Future Minimum Payments, Due in Five Years | 9.6 | ||
| Operating Leases, Future Minimum Payments, Due Thereafter | 121.5 | ||
| Operating Leases, Future Minimum Payments Due, Total | 173.2 | ||
| Capital Leases [Abstract] | |||
| Capital Leases, Future Minimum Payments Due, Next Twelve Months | 0.2 | ||
| Capital Leases, Future Minimum Payments Due in Two Years | 0.2 | ||
| Capital Leases, Future Minimum Payments Due in Three Years | 0.2 | ||
| Capital Leases, Future Minimum Payments Due in Four Years | 0.2 | ||
| Capital Leases, Future Minimum Payments Due in Five Years | 0.2 | ||
| Capital Leases, Future Minimum Payments Due Thereafter | 1.8 | ||
| Capital Leases, Future Minimum Payments Due, Total | 2.8 | ||
| Total Commitments [Abstract] | |||
| Total Commitments, Due in Next Twelve Months | 368.4 | ||
| Total Commitments, Due within Two Years | 299.0 | ||
| Total Commitments, Due within Three Years | 249.8 | ||
| Total Commitments, Due within Four Years | 263.5 | ||
| Total Commitments, Due within Five Years | 224.7 | ||
| Total Commitments, Due Thereafter | 570.1 | ||
| Total Commitments Due | 1,975.5 | ||
| Reimbursement by Other Owners per Year (2016) | 1.5 | ||
| Reimbursement By Other Owners in 2017 | 0.9 | ||
| Reimbursements by Other Owners per Year (2018 to 2025) | 0.4 | ||
| Reimbursements by Other Owners Total | 6.0 | ||
| Kansas City Power and Light Company [Member] | Supply Commitment [Member] | |||
| Total Commitments [Abstract] | |||
| Capacity Sales Agreements per Year 2016 | 6.0 | ||
| Capacity Sales Agreements per Year 2017 | 1.9 | ||
| Capacity Sales Agreements per Year 2018 | 2.1 | ||
| Capacity Sales Agreements per Year 2019 | 1.9 | ||
| Capacity Sales Agreements per Year 2020 | 2.0 | ||
| Kansas City Power and Light Company [Member] | Public Utilities, Inventory, Fuel [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 264.7 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 243.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 178.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 182.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 175.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 52.5 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 1,096.7 | ||
| Kansas City Power and Light Company [Member] | Purchased Power [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 34.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 34.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 34.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 34.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 34.8 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 359.8 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 533.8 | ||
| Kansas City Power and Light Company [Member] | Capacity [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 1.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 0.0 | ||
| Unrecorded Unconditional Purchase Obligation, Total | 1.2 | ||
| Kansas City Power and Light Company [Member] | Other purchase commitments [Member] | |||
| Purchase Commitments [Abstract] | |||
| Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 55.6 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Two Years | 10.2 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Three Years | 26.9 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Four Years | 36.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due within Five Years | 4.3 | ||
| Unrecorded Unconditional Purchase Obligation, Due after Five Years | 34.5 | ||
| Unrecorded Unconditional Purchase Obligation, Total | $ 167.8 | ||
| X | ||||||||||
- Definition Capacity sales agreements entered into by KCP&L for 2019 No definition available.
|
| X | ||||||||||
- Definition Capacity Sales Agreements per Year 2016 No definition available.
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- Definition Capacity Sales Agreements per Year 2017 No definition available.
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| X | ||||||||||
- Definition Capacity Sales Agreements per Year 2018 No definition available.
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| X | ||||||||||
- Definition Capacity Sales Agreements per Year 2020 No definition available.
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| X | ||||||||||
- Definition Reimbursement By Other Owners in 2016 No definition available.
|
| X | ||||||||||
- Definition Reimbursement By Other Owners in 2017 No definition available.
|
| X | ||||||||||
- Definition Reimbursements By Other Owners Per Year (2018 To 2025) No definition available.
|
| X | ||||||||||
- Definition Total reimbursement by other owners to KCP and L for leased property, plant, or equipment. No definition available.
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| X | ||||||||||
- Definition Total Commitments [Abstract] No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due. No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the twelve months after the balance sheet date. No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due following the fifth year after the balance sheet date. No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the fifth year after the balance sheet date. No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the fourth year after the balance sheet date. No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the third year after the balance sheet date. No definition available.
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| X | ||||||||||
- Definition The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the second year after the balance sheet date. No definition available.
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| X | ||||||||||
- Definition Amount of minimum lease payments for capital leases. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount of minimum lease payments for capital leases due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of minimum lease payments for capital leases due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of minimum lease payments for capital leases due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of minimum lease payments for capital leases due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of minimum lease payments for capital leases due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of minimum lease payments for capital leases due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Commitments and Contingencies Environmental Matters (Details) T in Millions, $ in Millions |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2015
USD ($)
T
MW
|
Dec. 31, 2014
USD ($)
|
|
| Estimated Environmental Capital Expenditures [Abstract] | ||
| Estimate Of Environmental Capital Expenditures Current | $ 99.6 | |
| Estimate Of Environmental Capital Expenditures In Two Years | 45.5 | |
| Estimate Of Environmental Capital Expenditures In Three Years | 20.6 | |
| Estimate Of Environmental Capital Expenditures In Four Years | 98.9 | |
| Estimate Of Environmental Capital Expenditures In Five Years | $ 151.9 | |
| Mercury and Air Toxics Standards Rule [Abstract] | ||
| Capacity of electric steam generating units that fall under MACT standards (in megawatts) | MW | 25 | |
| Climate Change [Abstract] | ||
| CO2 produced per year (in tons) | T | 21 | |
| EPA nationwide CO2 emission reductions by 2030 | 32.00% | |
| Remediation [Abstract] | ||
| Accrued environmental remediation expenses | $ 1.4 | $ 1.4 |
| MISSOURI | ||
| Climate Change [Abstract] | ||
| EPA Interim Co2 Goal Rate Reduction | 26.00% | |
| EPA Co2 Emission Reductions By 2030 By State | 37.00% | |
| KANSAS | ||
| Climate Change [Abstract] | ||
| EPA Interim Co2 Goal Rate Reduction | 34.00% | |
| EPA Co2 Emission Reductions By 2030 By State | 44.00% | |
| Kansas City Power and Light Company [Member] | ||
| Estimated Environmental Capital Expenditures [Abstract] | ||
| Estimate Of Environmental Capital Expenditures Current | $ 83.8 | |
| Estimate Of Environmental Capital Expenditures In Two Years | 30.1 | |
| Estimate Of Environmental Capital Expenditures In Three Years | 14.4 | |
| Estimate Of Environmental Capital Expenditures In Four Years | 87.3 | |
| Estimate Of Environmental Capital Expenditures In Five Years | $ 130.0 | |
| Climate Change [Abstract] | ||
| CO2 produced per year (in tons) | T | 15 | |
| Remediation [Abstract] | ||
| Accrued environmental remediation expenses | $ 0.3 | $ 0.3 |
| KCPL Greater Missouri Operations [Member] | ||
| Remediation [Abstract] | ||
| Estimated amount of insurance proceeds available to cover qualified remediation expenses | $ 1.4 |
| X | ||||||||||
- Definition New MACT rules will apply to all new or existing coal-fired electric generating units with a capacity equal to or greater than this amount. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Targeted reduction by state in CO2 emissions from the power sector by 2030 from 2012 emission levels as adjusted by the EPA as part of the EPA's Clean Power Plan. No definition available.
|
| X | ||||||||||
- Definition Targeted nationwide reductions in CO2 emissions from the power sector by 2030 from 2005 emission levels as part of the EPA's Clean Power Plan. No definition available.
|
| X | ||||||||||
- Definition The interim CO2 goal rate reduction (average of years 2022-2029) from 2012 CO2 emissions as adjusted by the EPA as part of the EPA's Clean Power Plan. No definition available.
|
| X | ||||||||||
- Definition Current estimate of capital expenditures (exclusive of Allowance for Funds Used During Construction and property taxes) to comply with environmental regulations in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
| X | ||||||||||
- Definition Current estimate of capital expenditures (exclusive of Allowance for Funds Used During Construction and property taxes) to comply with environmental regulations in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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| X | ||||||||||
- Definition Current estimate of capital expenditures (exclusive of Allowance for Funds Used During Construction and property taxes) to comply with environmental regulations in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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| X | ||||||||||
- Definition Current estimate of capital expenditures (exclusive of Allowance for Funds Used During Construction and property taxes) to comply with environmental regulations in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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| X | ||||||||||
- Definition Current estimate of capital expenditures (exclusive of Allowance for Funds Used During Construction and property taxes) to comply with environmental regulations in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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- Definition Represents the estimated amount of insurance proceeds available, less an annual deductible, to GMO cover qualified MGP remediation expenses. No definition available.
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- Definition Estimated Environmental Capital Expenditures [Abstract] No definition available.
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| X | ||||||||||
- Definition Represents the estimated number of tons of CO2 produced each year based on current generation capacity. No definition available.
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- Definition -- None. No documentation exists for this element. -- No definition available.
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- Definition Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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Legal Proceedings Loss Contingencies (Details) - MPS Merchant Services, Inc. [Member] $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
| |
| Loss Contingencies [Line Items] | |
| Approximate amount of refunds received as a net purchaser of power through settlements with sellers of power | $ 8 |
| Estimated additional refunds entitled to receive | $ 12 |
| Loss Contingency, Inestimable Loss | Due to the uncertainties remaining in the case, the loss or range of loss cannot be reasonably estimated |
| X | ||||||||||
- Definition Estimated additional refunds entitled to receive. No definition available.
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| X | ||||||||||
- Definition Amount of judgment or settlement awarded to (against) the entity in respect of litigation. No definition available.
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Explanation as to why an estimate of a specified contingent loss cannot be made, resulting in disclosure without accrual. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Guarantees (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
| |
| Guarantor Obligations [Line Items] | |
| Guarantor Obligations, Maximum Exposure, Undiscounted | $ 138.4 |
| Guarantor Obligations, Origin and Purpose | In the ordinary course of business, Great Plains Energy and certain of its subsidiaries enter into various agreements providing financial or performance assurance to third parties on behalf of certain subsidiaries. Such agreements include, for example, guarantees and letters of credit. These agreements are entered into primarily to support or enhance the creditworthiness otherwise attributed to a subsidiary on a stand-alone basis, thereby facilitating the extension of sufficient credit to accomplish the subsidiary's intended business purposes. |
| Direct Guarantee [Member] | |
| Guarantor Obligations [Line Items] | |
| Guarantor Obligations, Maximum Exposure, Undiscounted | $ 40.7 |
| Guarantor Obligations, Term | expire in 2016 |
| Guarantor Obligations, Origin and Purpose | direct guarantees to GMO counterparties |
| Guarantee of Indebtedness of Others [Member] | Long-term Debt [Member] | |
| Guarantor Obligations [Line Items] | |
| Guarantor Obligations, Maximum Exposure, Undiscounted | $ 97.7 |
| Guarantor Obligations, Term | maturity dates ranging from 2016 to 2023 |
| Guarantor Obligations, Origin and Purpose | guarantee of GMO long-term debt |
| Guarantee of Indebtedness of Others [Member] | Commercial Paper [Member] | |
| Guarantor Obligations [Line Items] | |
| Guarantor Obligations, Maximum Exposure, Undiscounted | $ 43.7 |
| Guarantor Obligations, Origin and Purpose | guaranteed GMO's commercial paper program |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Describes how and under what circumstances or in connection with which transaction the guarantee or each group of similar guarantees was given and the objective of the guarantee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Describe the approximate term of the guarantee or each group of similar guarantees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Related Party Transactions and Relationships (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Kansas City Power and Light Company [Member] | KCPL Greater Missouri Operations [Member] | |||
| Related Party Transaction [Line Items] | |||
| Related Party Transaction, Due from (to) Related Party, Current | $ 50.0 | $ 38.2 | |
| Operating expenses and capital costs billed from KCPL to GMO | 183.6 | 173.9 | $ 223.6 |
| KCPL net wholesale sales to GMO | 0.2 | 12.7 | $ 25.6 |
| Kansas City Power and Light Company [Member] | KCPL Greater Missouri Operations [Member] | Money Pool [Member] | |||
| Related Party Transaction [Line Items] | |||
| Payable to Related Party | 12.6 | ||
| Kansas City Power and Light Company [Member] | Great Plains Energy [Member] | |||
| Related Party Transaction [Line Items] | |||
| Related Party Transaction, Due from (to) Related Party, Current | $ 15.8 | $ 18.0 | |
| Iatan No 1 And 2 [Member] | KCPL Greater Missouri Operations [Member] | |||
| Related Party Transaction [Line Items] | |||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 18.00% | ||
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The proportionate share of interest (percent) in a jointly owned utility plant. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of transactions with related party during the financial reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Receivables to be collected from (obligations owed to) related parties, net as of the balance sheet date within one year where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
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- Definition Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period. No definition available.
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Derivative Instruments (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Futures contracts [Member] | Not Designated as Hedging Instrument [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Notional Contract Amount | $ 26.6 | $ 14.9 |
| Fair Value | (5.7) | (2.4) |
| Forward Contracts [Member] | Not Designated as Hedging Instrument [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Notional Contract Amount | 15.6 | 29.7 |
| Fair Value | 3.1 | 4.1 |
| Option contracts [Member] | Not Designated as Hedging Instrument [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Notional Contract Amount | 0.0 | 1.7 |
| Fair Value | 0.0 | 0.1 |
| Transmission Congestion Rights [Member] | Not Designated as Hedging Instrument [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Notional Contract Amount | 5.6 | 28.3 |
| Fair Value | (0.5) | 2.6 |
| Kansas City Power and Light Company [Member] | Futures contracts [Member] | Not Designated as Hedging Instrument [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Notional Contract Amount | 0.9 | 0.0 |
| Fair Value | (0.1) | 0.0 |
| Kansas City Power and Light Company [Member] | Transmission Congestion Rights [Member] | Not Designated as Hedging Instrument [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Notional Contract Amount | 4.1 | 23.6 |
| Fair Value | $ (0.4) | $ 3.1 |
| KCPL Greater Missouri Operations [Member] | ||
| Price Risk Derivatives [Abstract] | ||
| Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year one | 66.00% | |
| Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year two | 18.00% | |
| Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year three | 8.00% |
| X | ||||||||||
- Definition Percentage of expected on-peak natural gas and natural gas equivalent purchased power price exposure that is hedged for the year following the balance sheet date. No definition available.
|
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- Definition Percentage of projected natural gas usage hedged for the third year following the balance sheet date. No definition available.
|
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- Definition Percentage of expected on-peak natural gas and natural gas equivalent purchased power price exposure that is hedged for the second year following the balance sheet date. No definition available.
|
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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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Derivative Instruments Cash Flow Hedge (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
| |
| Derivative [Line Items] | |
| Cash Flow Hedge Loss to be Reclassified within Twelve Months | $ 9.2 |
| Kansas City Power and Light Company [Member] | |
| Derivative [Line Items] | |
| Cash Flow Hedge Loss to be Reclassified within Twelve Months | $ 8.8 |
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- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Derivative Instruments Offsetting Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Offsetting Assets [Line Items] | ||
| Derivative Asset, Fair Value, Gross Asset | $ 3.3 | $ 8.6 |
| Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset | (0.2) | (1.2) |
| Derivative Asset | 3.1 | 7.4 |
| Derivative, Collateral, Obligation to Return Securities | 0.0 | 0.0 |
| Derivative, Collateral, Obligation to Return Cash | 0.0 | 0.0 |
| Derivative Asset, Fair Value, Amount Offset Against Collateral | 3.1 | 7.4 |
| Kansas City Power and Light Company [Member] | ||
| Offsetting Assets [Line Items] | ||
| Derivative Asset, Fair Value, Gross Asset | 0.2 | 4.0 |
| Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset | (0.2) | (0.9) |
| Derivative Asset | 0.0 | 3.1 |
| Derivative, Collateral, Obligation to Return Securities | 0.0 | 0.0 |
| Derivative, Collateral, Obligation to Return Cash | 0.0 | 0.0 |
| Derivative Asset, Fair Value, Amount Offset Against Collateral | $ 0.0 | $ 3.1 |
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- Definition Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and obligation to return cash collateral under master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of obligation to return securities collateral under master netting arrangements that have not been offset against derivative assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after effects of master netting arrangements, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Derivative Instruments Offsetting Liabilities (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Offsetting Liabilities [Line Items] | ||
| Derivative Liability, Fair Value, Gross Liability | $ 6.4 | $ 4.2 |
| Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset | (5.9) | (3.5) |
| Derivative Liability | 0.5 | 0.7 |
| Derivative, Collateral, Right to Reclaim Securities | 0.0 | 0.0 |
| Derivative, Collateral, Right to Reclaim Cash | 0.0 | 0.0 |
| Derivative Liability, Fair Value, Amount Offset Against Collateral | 0.5 | 0.7 |
| Cash collateral posted with third parties as part of netting agreements | 5.7 | 2.3 |
| Kansas City Power and Light Company [Member] | ||
| Offsetting Liabilities [Line Items] | ||
| Derivative Liability, Fair Value, Gross Liability | 0.7 | 0.9 |
| Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset | (0.3) | (0.9) |
| Derivative Liability | 0.4 | 0.0 |
| Derivative, Collateral, Right to Reclaim Securities | 0.0 | 0.0 |
| Derivative, Collateral, Right to Reclaim Cash | 0.0 | 0.0 |
| Derivative Liability, Fair Value, Amount Offset Against Collateral | $ 0.4 | $ 0.0 |
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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of right to receive securities collateral under master netting arrangements that have not been offset against derivative liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after effects of master netting arrangements, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against the right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and right to receive cash collateral under master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Derivative Instruments Fair Value (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Derivatives, Fair Value [Line Items] | ||
| Derivative Asset, Fair Value, Gross Asset | $ 3.3 | $ 8.6 |
| Derivative Liability, Fair Value, Gross Liability | 6.4 | 4.2 |
| Kansas City Power and Light Company [Member] | ||
| Derivatives, Fair Value [Line Items] | ||
| Derivative Asset, Fair Value, Gross Asset | 0.2 | 4.0 |
| Derivative Liability, Fair Value, Gross Liability | 0.7 | 0.9 |
| Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Balance Sheet Location [Member] | ||
| Derivatives, Fair Value [Line Items] | ||
| Derivative Asset, Fair Value, Gross Asset | 3.3 | 8.6 |
| Derivative Liability, Fair Value, Gross Liability | 6.4 | 4.2 |
| Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Balance Sheet Location [Member] | Kansas City Power and Light Company [Member] | ||
| Derivatives, Fair Value [Line Items] | ||
| Derivative Asset, Fair Value, Gross Asset | 0.2 | 4.0 |
| Derivative Liability, Fair Value, Gross Liability | $ 0.7 | $ 0.9 |
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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Derivative Instruments Gain and Losses (Details) - Not Designated as Hedging Instrument [Member] - Commodity Contract [Member] - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement or regulatory account for changes in fair value of commodity contracts not designated as hedging | $ (19.0) | $ (20.3) | $ (0.9) |
| Regulatory Asset [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Amount of gain (loss) recognized in regulatory account for changes in fair value of commodity contracts not designated as hedging | (6.8) | (2.7) | 0.0 |
| Regulatory Liability [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Amount of gain (loss) recognized in regulatory account for changes in fair value of commodity contracts not designated as hedging | 0.0 | 0.0 | 0.2 |
| Kansas City Power and Light Company [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement or regulatory account for changes in fair value of commodity contracts not designated as hedging | (7.2) | (13.3) | 0.8 |
| Kansas City Power and Light Company [Member] | Regulatory Asset [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Amount of gain (loss) recognized in regulatory account for changes in fair value of commodity contracts not designated as hedging | (0.5) | (0.2) | 0.0 |
| Purchased Power Costs [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement for changes in fair value of commodity contracts not designated as hedging | (1.5) | (4.9) | 0.0 |
| Fuel Costs [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement for changes in fair value of commodity contracts not designated as hedging | (2.5) | 1.5 | (1.1) |
| Fuel Costs [Member] | Kansas City Power and Light Company [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement for changes in fair value of commodity contracts not designated as hedging | 1.5 | 1.1 | 0.8 |
| Electric Revenues [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement for changes in fair value of commodity contracts not designated as hedging | (8.2) | (14.2) | 0.0 |
| Electric Revenues [Member] | Kansas City Power and Light Company [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) reflected in the income statement for changes in fair value of commodity contracts not designated as hedging | $ (8.2) | $ (14.2) | $ 0.0 |
| X | ||||||||||
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement or a regulatory asset/liability. No definition available.
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- Definition Gains and losses (net) on derivative instruments that were recognized in a regulatory account during the current period. No definition available.
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements Level 3 (Details) - Derivative Financial Instruments, Assets [Member] - Fair Value, Inputs, Level 3 [Member] - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Net asset (liability) beginning of period | $ 3.5 | $ 3.3 |
| Purchases | 0.0 | 16.0 |
| Settlements | (2.0) | (11.2) |
| Net asset (liability) end of period | (0.1) | 3.5 |
| Purchased Power Costs [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | (1.5) | (4.9) |
| Non-Operating Income [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | 8.6 | 14.6 |
| Total unrealized gains and (losses) relating to assets and liabilities still on the consolidated balance sheet at period end | (0.2) | (0.3) |
| Electric Revenues [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | (8.2) | (14.2) |
| Total unrealized gains and (losses) relating to assets and liabilities still on the consolidated balance sheet at period end | 0.0 | (0.2) |
| Regulatory Asset [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Regulatory Account | (0.5) | (0.1) |
| Total unrealized gains and (losses) relating to assets and liabilities still on the consolidated balance sheet at period end | (0.5) | (0.1) |
| Kansas City Power and Light Company [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Net asset (liability) beginning of period | 3.1 | 1.1 |
| Purchases | (0.8) | 13.7 |
| Settlements | 5.9 | 2.7 |
| Net asset (liability) end of period | (0.4) | 3.1 |
| Kansas City Power and Light Company [Member] | Electric Revenues [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | (8.2) | (14.2) |
| Total unrealized gains and (losses) relating to assets and liabilities still on the consolidated balance sheet at period end | 0.0 | (0.2) |
| Kansas City Power and Light Company [Member] | Regulatory Asset [Member] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Regulatory Account | (0.4) | (0.2) |
| Total unrealized gains and (losses) relating to assets and liabilities still on the consolidated balance sheet at period end | $ (0.4) | $ (0.2) |
| X | ||||||||||
- Definition Amount of gain (loss) recognized in a regulatory account of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. No definition available.
|
| X | ||||||||||
- Definition Amount of unrealized (holding) gain (loss) which is included in the statement of income (or changes in net assets) related to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of gain (loss) recognized in the income statement of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements Fair Value Long-Term Debt (Details) - USD ($) $ in Billions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Carrying (Reported) Amount, Fair Value Disclosure [Member] | ||
| Fair value of financial instruments [Abstract] | ||
| Long-term Debt | $ 3.7 | $ 3.5 |
| Carrying (Reported) Amount, Fair Value Disclosure [Member] | Kansas City Power and Light Company [Member] | ||
| Fair value of financial instruments [Abstract] | ||
| Long-term Debt | 2.6 | 2.3 |
| Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] | ||
| Fair value of financial instruments [Abstract] | ||
| Long-term debt fair value | 4.0 | 3.8 |
| Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] | Kansas City Power and Light Company [Member] | ||
| Fair value of financial instruments [Abstract] | ||
| Long-term debt fair value | $ 2.8 | $ 2.6 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. No definition available.
|
| X | ||||||||||
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Fair Value Measurements (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | $ 3.3 | $ 8.6 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | 6.4 | 4.2 | |||||||||
| Kansas City Power and Light Company [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | 0.2 | 4.0 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | 0.7 | 0.9 | |||||||||
| Other Great Plains [Member] | Fixed Income Funds [Member] | |||||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| Alternative Investments, Fair Value Disclosure | 16.6 | 17.8 | |||||||||
| Fair Value, Measurements, Recurring [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 3.3 | 8.6 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | [2] | 200.7 | 199.0 | ||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | [3] | 13.6 | 15.1 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | [4] | 0.1 | 0.1 | ||||||||
| Total assets | 217.7 | 222.8 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 6.4 | 4.2 | ||||||||
| Total liabilities | 6.4 | 4.2 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.0 | 0.0 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | [2] | 165.4 | 162.3 | ||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | [3] | 6.3 | 7.5 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | [4] | 0.1 | 0.1 | ||||||||
| Total assets | 171.8 | 169.9 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 5.7 | 2.4 | ||||||||
| Total liabilities | 5.7 | 2.4 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 2.7 | 3.4 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | [2] | 35.3 | 36.7 | ||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | [3] | 7.3 | 7.6 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | [4] | 0.0 | 0.0 | ||||||||
| Total assets | 45.3 | 47.7 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.0 | 0.1 | ||||||||
| Total liabilities | 0.0 | 0.1 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.6 | 5.2 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | [2] | 0.0 | 0.0 | ||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | [3] | 0.0 | 0.0 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | [4] | 0.0 | 0.0 | ||||||||
| Total assets | 0.6 | 5.2 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.7 | 1.7 | ||||||||
| Total liabilities | 0.7 | 1.7 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.2 | 4.0 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 200.7 | 199.0 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 13.6 | 15.1 | |||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| Total assets | 214.5 | 218.1 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.7 | 0.9 | ||||||||
| Total liabilities | 0.7 | 0.9 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Equity Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 135.4 | 137.1 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 1.1 | 1.3 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Debt Securities [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 7.3 | 7.6 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | US Treasury and Government [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 26.4 | 22.9 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | US Government Corporations and Agencies Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 1.8 | 3.5 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | US States and Political Subdivisions Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 4.0 | 4.1 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Corporate Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 29.2 | 28.1 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Foreign Government Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.3 | 0.5 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Cash Equivalents [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 3.6 | 2.3 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Cash and Cash Equivalents [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 5.2 | 6.2 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Other Trust Assets [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.5 | ||||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.0 | 0.0 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 165.4 | 162.3 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 6.3 | 7.5 | |||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| Total assets | 171.7 | 169.8 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.1 | 0.0 | ||||||||
| Total liabilities | 0.1 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 135.4 | 137.1 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 1.1 | 1.3 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury and Government [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 26.4 | 22.9 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Corporations and Agencies Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Cash Equivalents [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 3.6 | 2.3 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 5.2 | 6.2 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Other Trust Assets [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | ||||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.0 | 0.0 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 35.3 | 36.7 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 7.3 | 7.6 | |||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| Total assets | 42.6 | 44.3 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.0 | 0.0 | ||||||||
| Total liabilities | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 7.3 | 7.6 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury and Government [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Corporations and Agencies Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 1.8 | 3.5 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 4.0 | 4.1 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 29.2 | 28.1 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.3 | 0.5 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Cash Equivalents [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Other Trust Assets [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.5 | ||||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.2 | 4.0 | ||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| Total assets | 0.2 | 4.0 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.6 | 0.9 | ||||||||
| Total liabilities | 0.6 | 0.9 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury and Government [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Corporations and Agencies Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt Securities [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Cash Equivalents [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member] | |||||||||||
| Self-insured health plan trust [Abstract] | |||||||||||
| Self Insured Health Plan Trust Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Kansas City Power and Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Other Trust Assets [Member] | |||||||||||
| Nuclear decommissioning trust [Abstract] | |||||||||||
| Decommissioning Fund Investments, Fair Value | 0.0 | ||||||||||
| Fair Value, Measurements, Recurring [Member] | Other Great Plains [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 3.1 | 4.6 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | 0.1 | 0.1 | |||||||||
| Total assets | 3.2 | 4.7 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 5.7 | 3.3 | ||||||||
| Total liabilities | 5.7 | 3.3 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Other Great Plains [Member] | Fair Value, Inputs, Level 1 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.0 | 0.0 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | 0.1 | 0.1 | |||||||||
| Total assets | 0.1 | 0.1 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 5.6 | 2.4 | ||||||||
| Total liabilities | 5.6 | 2.4 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Other Great Plains [Member] | Fair Value, Inputs, Level 2 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 2.7 | 3.4 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Total assets | 2.7 | 3.4 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.0 | 0.1 | ||||||||
| Total liabilities | 0.0 | 0.1 | |||||||||
| Fair Value, Measurements, Recurring [Member] | Other Great Plains [Member] | Fair Value, Inputs, Level 3 [Member] | |||||||||||
| Assets [Abstract] | |||||||||||
| Derivative instruments, assets | [1] | 0.4 | 1.2 | ||||||||
| SERP rabbi trust [Abstract] | |||||||||||
| SERP Rabbi Trusts, Fair Value Disclosure | 0.0 | 0.0 | |||||||||
| Total assets | 0.4 | 1.2 | |||||||||
| Liabilities [Abstract] | |||||||||||
| Derivative instruments, liabilities | [1] | 0.1 | 0.8 | ||||||||
| Total liabilities | $ 0.1 | $ 0.8 | |||||||||
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- References No definition available.
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| X | ||||||||||
- Definition The fair value of investments held in a trust for KCP&L's self-insurance health plan. No definition available.
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| X | ||||||||||
- Definition Self-insured health plan trust [Abstract] No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The fair value of equity investments held in rabbi trusts related to GMO's Supplemental Executive Retirement Plan (SERP). No definition available.
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| X | ||||||||||
- Definition Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. No definition available.
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| X | ||||||||||
- Definition The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Aggregation of the liabilities reported on the balance sheet measured at fair value on a recurring basis by the entity. No definition available.
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Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions |
12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
||||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||||||
| Beginning balance | [1] | $ (18.7) | $ (25.3) | |||||
| Other comprehensive income (loss) before reclassifications | [1] | 0.6 | (1.8) | |||||
| Amounts reclassified from accumulated other comprehensive loss | [1] | 6.1 | 8.4 | |||||
| Net current period other comprehensive income | 6.7 | [1] | 6.6 | [1] | $ 13.1 | |||
| Ending balance | [1] | (12.0) | (18.7) | (25.3) | ||||
| Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | ||||||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||||||
| Beginning balance | [1] | (15.8) | (23.8) | |||||
| Other comprehensive income (loss) before reclassifications | [1] | 0.0 | 0.0 | |||||
| Amounts reclassified from accumulated other comprehensive loss | [1] | 5.7 | 8.0 | |||||
| Net current period other comprehensive income | [1] | 5.7 | 8.0 | |||||
| Ending balance | [1] | (10.1) | (15.8) | (23.8) | ||||
| Accumulated Defined Benefit Plans Adjustment [Member] | ||||||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||||||
| Beginning balance | [1] | (2.9) | (1.5) | |||||
| Other comprehensive income (loss) before reclassifications | [1] | 0.6 | (1.8) | |||||
| Amounts reclassified from accumulated other comprehensive loss | [1] | 0.4 | 0.4 | |||||
| Net current period other comprehensive income | [1] | 1.0 | (1.4) | |||||
| Ending balance | [1] | (1.9) | (2.9) | (1.5) | ||||
| Kansas City Power and Light Company [Member] | ||||||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||||||
| Beginning balance | (14.9) | |||||||
| Net current period other comprehensive income | 5.3 | 5.3 | 5.6 | |||||
| Ending balance | (9.6) | (14.9) | ||||||
| Kansas City Power and Light Company [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | ||||||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||||||
| Beginning balance | [1] | (14.9) | (20.2) | |||||
| Amounts reclassified from accumulated other comprehensive loss | [1] | 5.3 | 5.3 | |||||
| Net current period other comprehensive income | [1] | 5.3 | 5.3 | |||||
| Ending balance | [1] | $ (9.6) | $ (14.9) | $ (20.2) | ||||
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after tax, before reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after tax of reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Accumulated Other Comprehensive Income (Loss) Reclassification (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Interest charges | $ (199.3) | $ (188.5) | $ (198.4) | ||||||||
| Fuel | (421.4) | (489.2) | (539.5) | ||||||||
| Utility operating and maintenance expenses | (724.8) | (701.9) | (671.4) | ||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | 334.5 | 358.5 | 379.6 | ||||||||
| Income tax (expense) benefit | (122.7) | (115.7) | (129.2) | ||||||||
| Net income (loss) | $ 22.9 | $ 126.8 | $ 44.4 | $ 18.9 | $ 19.5 | $ 147.4 | $ 52.1 | $ 23.8 | |||
| Reclassification out of Accumulated Other Comprehensive Income [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Net income (loss) | (6.1) | (8.4) | |||||||||
| Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | (9.2) | (13.1) | |||||||||
| Income tax (expense) benefit | 3.5 | 5.1 | |||||||||
| Net income (loss) | (5.7) | (8.0) | |||||||||
| Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Contract [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Interest charges | (9.2) | (13.1) | |||||||||
| Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Utility operating and maintenance expenses | (0.7) | (0.6) | |||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | (0.7) | (0.6) | |||||||||
| Income tax (expense) benefit | 0.3 | 0.2 | |||||||||
| Net income (loss) | (0.4) | (0.4) | |||||||||
| Kansas City Power and Light Company [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Interest charges | (135.6) | (124.1) | (125.3) | ||||||||
| Fuel | (304.5) | (364.9) | (383.0) | ||||||||
| Utility operating and maintenance expenses | (494.2) | (489.1) | (475.9) | ||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | 229.6 | 238.1 | 248.8 | ||||||||
| Income tax (expense) benefit | (76.8) | (75.7) | $ (79.8) | ||||||||
| Net income (loss) | $ 25.9 | $ 84.3 | $ 29.4 | $ 13.2 | $ 15.9 | $ 94.5 | $ 34.8 | $ 17.2 | |||
| Kansas City Power and Light Company [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | (8.7) | (8.7) | |||||||||
| Income tax (expense) benefit | 3.4 | 3.4 | |||||||||
| Net income (loss) | (5.3) | (5.3) | |||||||||
| Kansas City Power and Light Company [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Contract [Member] | |||||||||||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||||||||||
| Interest charges | $ (8.7) | $ (8.7) | |||||||||
| X | ||||||||||
- Definition Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the cost of borrowed funds accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Amount of operating expense for fuel used by regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of operating expense for routine plant maintenance, repairs and operations of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Income Tax Expense (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Current income taxes | |||
| Federal | $ (0.2) | $ 0.4 | $ 0.3 |
| State | (1.1) | (0.1) | (3.0) |
| Current Income Tax Expense (Benefit), Total | (1.3) | 0.3 | (2.7) |
| Deferred income taxes | |||
| Federal | 96.9 | 104.2 | 109.1 |
| State | 28.0 | 21.6 | 24.9 |
| Deferred Income Tax Expense (Benefit), Total | 124.9 | 125.8 | 134.0 |
| Noncurrent income taxes | |||
| Federal | 0.0 | (2.4) | 0.0 |
| State | 0.0 | (0.5) | (0.3) |
| Foreign | 0.0 | (6.1) | (0.4) |
| Noncurrent Income Tax Expense (Benefit), Total | 0.0 | (9.0) | (0.7) |
| Investment tax credit | |||
| Deferral | 0.5 | 0.0 | 0.3 |
| Amortization | (1.4) | (1.4) | (1.7) |
| Investment Tax Credit, Total | (0.9) | (1.4) | (1.4) |
| Total income tax expense | $ 122.7 | $ 115.7 | $ 129.2 |
| Effective Income Tax Rate Reconciliation, Percent [Abstract] | |||
| Federal statutory income tax (in hundredths) | 35.00% | 35.00% | 35.00% |
| Differences between book and tax depreciation not normalized (in hundredths) | 0.00% | (0.70%) | (0.30%) |
| Amortization of investments tax credits (in hundredths) | (0.40%) | (0.40%) | (0.40%) |
| Federal income tax credits (in hundredths) | (4.10%) | (3.80%) | (3.50%) |
| State income taxes (in hundredths) | 4.00% | 3.80% | 3.80% |
| Changes in uncertain tax positions, net (in hundredths) | 0.00% | (1.70%) | (0.20%) |
| Valuation allowance | 1.50% | 0.00% | 0.00% |
| Effective Income Tax Rate Reconciliation, Other Adjustments | 0.50% | 0.10% | (0.40%) |
| Effective Income Tax Rate Reconciliation, Percent | 36.50% | 32.30% | 34.00% |
| Kansas City Power and Light Company [Member] | |||
| Current income taxes | |||
| Federal | $ (18.7) | $ (9.4) | $ (0.5) |
| State | (3.4) | (2.3) | (0.5) |
| Current Income Tax Expense (Benefit), Total | (22.1) | (11.7) | (1.0) |
| Deferred income taxes | |||
| Federal | 81.9 | 72.6 | 75.8 |
| State | 17.5 | 15.8 | 16.3 |
| Deferred Income Tax Expense (Benefit), Total | 99.4 | 88.4 | 92.1 |
| Noncurrent income taxes | |||
| Federal | 0.0 | 0.0 | (9.0) |
| State | 0.0 | 0.0 | (1.5) |
| Noncurrent Income Tax Expense (Benefit), Total | 0.0 | 0.0 | (10.5) |
| Investment tax credit | |||
| Deferral | 0.5 | 0.0 | 0.3 |
| Amortization | (1.0) | (1.0) | (1.1) |
| Investment Tax Credit, Total | (0.5) | (1.0) | (0.8) |
| Total income tax expense | $ 76.8 | $ 75.7 | $ 79.8 |
| Effective Income Tax Rate Reconciliation, Percent [Abstract] | |||
| Federal statutory income tax (in hundredths) | 35.00% | 35.00% | 35.00% |
| Differences between book and tax depreciation not normalized (in hundredths) | 0.00% | (0.90%) | (0.80%) |
| Amortization of investments tax credits (in hundredths) | (0.50%) | (0.40%) | (0.40%) |
| Federal income tax credits (in hundredths) | (5.60%) | (5.60%) | (5.30%) |
| State income taxes (in hundredths) | 4.00% | 3.70% | 3.70% |
| Valuation allowance | 0.30% | 0.00% | 0.00% |
| Effective Income Tax Rate Reconciliation, Other Adjustments | 0.30% | 0.00% | (0.10%) |
| Effective Income Tax Rate Reconciliation, Percent | 33.50% | 31.80% | 32.10% |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The amount deducted from an entities' taxes, reflecting a percentage of an amount invested in certain assets spread over the useful life of those assets; the part related to the amortization of investment tax credits. No definition available.
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| X | ||||||||||
- Definition The amount deducted from an entities' taxes, reflecting a percentage of an amount invested in certain assets spread over the useful life of those assets; the part related to the deferral of investment tax credits. No definition available.
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| X | ||||||||||
- Definition Total investment tax credit included in current tax expense. No definition available.
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| X | ||||||||||
- Definition The noncurrent component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted federal tax law to the domestic taxable Income or Loss from continuing operations. No definition available.
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| X | ||||||||||
- Definition The noncurrent component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of foreign enacted tax law to the foreign taxable Income or Loss from continuing operations. No definition available.
|
| X | ||||||||||
- Definition The noncurrent component of income tax expense for the period representing amounts of income taxes paid or payable (or refundable) for the period for all income tax obligations as determined by applying the provisions of relevant enacted tax laws to relevant amounts of taxable Income or Loss from continuing operations. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The noncurrent component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted state and local tax law to relevant amounts of taxable Income or Loss from continuing operations. No definition available.
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| X | ||||||||||
- Definition Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to depreciation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income tax contingencies. Includes, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to investment tax credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other tax credits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
Taxes Deferred Income Taxes (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|||
|---|---|---|---|---|---|
| Deferred Tax Assets (Liabilities), Net of Valuation Allowance, Current Classification [Abstract] | |||||
| Net operating loss carryforward, current | $ 0.0 | $ 62.2 | |||
| Deferred tax assets (liabilities), other current | 0.0 | 17.1 | |||
| Deferred tax assets (liabilities), before valuation allowance, current | 0.0 | 79.3 | |||
| Valuation allowance, current | 0.0 | (1.2) | |||
| Current deferred income tax asset | [1] | 0.0 | 78.1 | ||
| Deferred Tax Assets (Liabilities), Net of Valuation Allowance, Noncurrent Classification [Abstract] | |||||
| Plant related | (1,967.0) | (1,648.2) | |||
| Income taxes on future regulatory recoveries | (151.3) | (133.4) | |||
| Derivative instruments | 20.5 | 26.5 | |||
| Pension and post-retirement benefits | (0.1) | (14.0) | |||
| SO2 emission allowance sales | 25.7 | 27.1 | |||
| Tax credit carryforwards | 256.8 | 242.7 | |||
| Customer demand programs | (22.7) | (26.2) | |||
| Solar rebates | (31.9) | (33.2) | |||
| Net operating loss carryforward, noncurrent | 734.9 | 524.7 | |||
| Deferred Tax Liabilities, Other | (3.8) | (40.3) | |||
| Net noncurrent deferred income tax liability before valuation allowance | (1,138.9) | (1,074.3) | |||
| Valuation allowance, noncurrent | (19.9) | (15.4) | |||
| Net noncurrent deferred income tax liability | (1,158.8) | (1,089.7) | |||
| Net deferred income tax liability | (1,158.8) | (1,011.6) | |||
| Deferred Tax Assets (Liabilities), Gross [Abstract] | |||||
| Gross deferred income tax assets | 1,368.5 | 1,227.0 | |||
| Gross deferred income tax liabilities | (2,527.3) | (2,238.6) | |||
| Net deferred income tax liability | (1,158.8) | (1,011.6) | |||
| Kansas City Power and Light Company [Member] | |||||
| Deferred Tax Assets (Liabilities), Net of Valuation Allowance, Current Classification [Abstract] | |||||
| Net operating loss carryforward, current | 0.0 | 0.0 | |||
| Deferred tax assets (liabilities), other current | 0.0 | 5.0 | |||
| Deferred tax assets (liabilities), before valuation allowance, current | 0.0 | 5.0 | |||
| Valuation allowance, current | 0.0 | 0.0 | |||
| Current deferred income tax asset | [1] | 0.0 | 5.0 | ||
| Deferred Tax Assets (Liabilities), Net of Valuation Allowance, Noncurrent Classification [Abstract] | |||||
| Plant related | (1,398.9) | (1,167.3) | |||
| Income taxes on future regulatory recoveries | (125.0) | (107.1) | |||
| Derivative instruments | 14.0 | 18.9 | |||
| Pension and post-retirement benefits | 27.4 | 12.5 | |||
| SO2 emission allowance sales | 25.7 | 27.3 | |||
| Tax credit carryforwards | 166.6 | 153.2 | |||
| Customer demand programs | (16.9) | (19.0) | |||
| Solar rebates | (13.1) | (11.3) | |||
| Net operating loss carryforward, noncurrent | 204.2 | 98.5 | |||
| Deferred Tax Liabilities, Other | (15.9) | (22.6) | |||
| Net noncurrent deferred income tax liability before valuation allowance | (1,131.9) | (1,016.9) | |||
| Valuation allowance, noncurrent | (0.7) | 0.0 | |||
| Net noncurrent deferred income tax liability | (1,132.6) | (1,016.9) | |||
| Net deferred income tax liability | (1,132.6) | (1,011.9) | |||
| Deferred Tax Assets (Liabilities), Gross [Abstract] | |||||
| Gross deferred income tax assets | 740.9 | 624.8 | |||
| Gross deferred income tax liabilities | (1,873.5) | (1,636.7) | |||
| Net deferred income tax liability | $ (1,132.6) | $ (1,011.9) | |||
| |||||
| X | ||||||||||
- Definition The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset. No definition available.
|
| X | ||||||||||
- Definition The amount as of the balance sheet date of the estimated future tax effects attributable to the sales of SO 2 emission allowances. No definition available.
|
| X | ||||||||||
- Definition Amount of current deferred tax asset attributable to deductible temporary differences and carryforwards, net of current deferred tax liability attributable to taxable temporary differences before allocation of valuation allowances. No definition available.
|
| X | ||||||||||
- Definition Amount of noncurrent deferred tax asset attributable to deductible temporary differences and carryforwards, net of noncurrent deferred tax liability attributable to taxable temporary differences before allocation of valuation allowances. No definition available.
|
| X | ||||||||||
- Definition The tax effect as of the balance sheet date of the amount of estimated future tax deductions or taxable amounts arising from other temporary differences not otherwise specified in the taxonomy. No definition available.
|
| X | ||||||||||
- Definition The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which can be used on the tax returns within the next twelve months to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset. No definition available.
|
| X | ||||||||||
- Definition The amount as of the balance sheet date of the estimated future tax effects attributable to customer demand programs. No definition available.
|
| X | ||||||||||
- Definition The amount as of the balance sheet date of the estimated future tax effects attributable to solar rebates paid to customers. No definition available.
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from derivative instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, netted by jurisdiction and classified as current. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from pension benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences, before jurisdictional netting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences, netted by jurisdiction and classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from regulatory assets and liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
Taxes Net Operating Loss Carryforwards (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Internal Revenue Service (IRS) [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Operating Loss Carryforwards | $ 656.1 | $ 521.0 |
| Amount of Net Operating Losses related to business acquisition | 313.2 | 312.2 |
| Operating Loss Carryforwards, Valuation Allowance | 0.9 | |
| Net operating losses year of origination [Abstract] | ||
| Net operating loss carryforwards originating in 2003 | 30.1 | |
| Net operating loss carryfowards originating in 2004 | 152.4 | |
| Net operating loss carryfowards originating in 2005 | 74.1 | |
| Net operating loss carryfowards originating in 2006 | 53.3 | |
| Net operating loss carryfowards originating in 2007 | 1.3 | |
| Net operating loss carryfowards originating in 2008 | 2.4 | |
| Net operating loss carryfowards originating in 2009 | 36.5 | |
| Net operating loss carryfowards originating in 2010 | 4.1 | |
| Net operating loss carryfowards originating in 2011 | 109.7 | |
| Net operating loss carryforwards originating in 2012 | 2.5 | |
| Net operating loss carryforwards originating in 2013 | 2.3 | |
| Net operating loss carryforwards originating in 2014 | 86.3 | |
| Net operating loss carry forwards originating in 2015 | $ 101.1 | |
| Internal Revenue Service (IRS) [Member] | Minimum [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Operating Loss Carryforwards, Expiration Date | Dec. 31, 2023 | |
| Internal Revenue Service (IRS) [Member] | Maximum [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Operating Loss Carryforwards, Expiration Date | Dec. 31, 2035 | |
| State and Local Jurisdiction [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Operating Loss Carryforwards | $ 78.8 | 65.9 |
| Amount of Net Operating Losses related to business acquisition | 39.2 | $ 40.7 |
| Operating Loss Carryforwards, Valuation Allowance | $ 18.6 |
| X | ||||||||||
- Definition The amount of net operating loss carryforwards acquired in in the GMO acquisition. No definition available.
|
| X | ||||||||||
- Definition Net Operating Loss Carry Forwards Originating in 2015 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2003 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryforwards originating in 2012 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryforwards originating in 2013. No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryforwards originating in 2014 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2004 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2005 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2006 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2007 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2008 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2009 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2010 No definition available.
|
| X | ||||||||||
- Definition Net operating loss carryfowards originating in 2011 No definition available.
|
| X | ||||||||||
- Definition Net operating losses year of origination [Abstract] No definition available.
|
| X | ||||||||||
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Expiration date of each operating loss carryforward included in operating loss carryforward, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Taxes Tax Credit Carryforwards (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Tax Credit Carryforward [Line Items] | ||
| Valuation Allowance, Deferred Tax Asset, Explanation of Change | tax expense was recorded in continuing operations primarily related to state NOL carryforwards that the Company expects to expire unutilized due to the extension of bonus depreciation through 2019. | |
| General Business Tax Credit Carryforward [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Amount | $ 169.2 | $ 155.1 |
| Amount of tax credit acquired in business combination | $ 0.5 | $ 0.5 |
| Tax Credit Carryforward, Description | relate primarily to Advanced Coal Investment Tax Credits and Wind Production tax credits | relate primarily to Advanced Coal Investment Tax Credits and Wind Production tax credits |
| Tax Credit Carryforward, Valuation Allowance | $ 0.4 | $ 0.4 |
| General Business Tax Credit Carryforward [Member] | Minimum [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Expiration Date | Dec. 31, 2028 | |
| General Business Tax Credit Carryforward [Member] | Maximum [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Expiration Date | Dec. 31, 2035 | |
| Federal Alternative Minimum Tax Credit Carryforward [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Amount | $ 87.6 | 87.6 |
| Amount of tax credit acquired in business combination | $ 87.6 | $ 87.6 |
| Tax Credit Carryforward, Description | These credits do not expire and can be used to reduce taxes paid in the future. | These credits do not expire and can be used to reduce taxes paid in the future. |
| Kansas City Power and Light Company [Member] | General Business Tax Credit Carryforward [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Amount | $ 166.6 | $ 153.2 |
| Tax Credit Carryforward, Description | relate primarily to Advanced Coal Investment Tax Credits and Wind Production tax credits | relate primarily to Advanced Coal Investment Tax Credits and Wind Production tax credits |
| Kansas City Power and Light Company [Member] | General Business Tax Credit Carryforward [Member] | Minimum [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Expiration Date | Dec. 31, 2028 | |
| Kansas City Power and Light Company [Member] | General Business Tax Credit Carryforward [Member] | Maximum [Member] | ||
| Tax Credit Carryforward [Line Items] | ||
| Tax Credit Carryforward, Expiration Date | Dec. 31, 2035 | |
| X | ||||||||||
- Definition Amount of tax credit acquired in GMO acquisition No definition available.
|
| X | ||||||||||
- Definition The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A description of the origin, nature, and characteristics of the tax credit carryforward. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Expiration date of the tax credit carryforward, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from tax credit carryforwards for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A description of and reason for the change during the period in the valuation allowance for a specified deferred tax asset. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Taxes Valuation Allowance (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
| |
| Valuation Allowance [Line Items] | |
| Valuation Allowance, Deferred Tax Asset, Change in Amount | $ 3.3 |
| Valuation Allowance, Deferred Tax Asset, Explanation of Change | tax expense was recorded in continuing operations primarily related to state NOL carryforwards that the Company expects to expire unutilized due to the extension of bonus depreciation through 2019. |
| X | ||||||||||
- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A description of and reason for the change during the period in the valuation allowance for a specified deferred tax asset. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
Taxes Uncertain Tax Positions (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Uncertain Tax Positions [Line Items] | |||
| Amount expected to impact the effective tax rate if recognized | $ 0.3 | $ 0.3 | $ 6.5 |
| Unrecognized Tax Benefits, Period Decrease | 7.2 | ||
| Unrecognized tax benefit decrease related to former GMO non-regulated operations | 6.1 | ||
| Unrecognized Tax Benefits, Income Tax Penalties Accrued | 0.0 | 0.0 | 0.6 |
| Unrecognized Tax Benefits, Interest on Income Taxes Accrued | 0.0 | 0.0 | 3.2 |
| Interest expense related to unrecognized tax benefits | 0.0 | 3.2 | 0.1 |
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Balance at beginning of period | 2.6 | 9.8 | 21.4 |
| Reductions for current year tax positions | (0.3) | (0.3) | (0.3) |
| Reductions for prior year tax positions | 0.0 | (6.9) | (10.5) |
| Statute expirations | 0.0 | 0.0 | (0.3) |
| Foreign currency translation adjustments | 0.0 | 0.0 | (0.5) |
| Balance at end of period | $ 2.3 | $ 2.6 | $ 9.8 |
| X | ||||||||||
- Definition Increase or decrease in unrecognized tax benefits related to former GMO non-regulated operations. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from foreign currency translation. No definition available.
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of interest expense accrued for an underpayment of income taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of interest expense for an underpayment of income taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The net amount of all increases and decreases in unrecognized tax benefits for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
Segments and Related Information (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Segment Reporting Information [Line Items] | |||||||||||
| Operating revenues | $ 562.7 | $ 781.4 | $ 609.0 | $ 549.1 | $ 552.2 | $ 782.5 | $ 648.4 | $ 585.1 | $ 2,502.2 | $ 2,568.2 | $ 2,446.3 |
| Depreciation and amortization | (330.4) | (306.0) | (289.7) | ||||||||
| Interest (charges) income | (199.3) | (188.5) | (198.4) | ||||||||
| Income tax (expense) benefit | (122.7) | (115.7) | (129.2) | ||||||||
| Net income (loss) | 213.0 | 242.8 | 250.2 | ||||||||
| Assets, Total | 10,738.6 | 10,453.4 | 10,738.6 | 10,453.4 | 9,770.2 | ||||||
| Capital expenditures | 677.1 | 773.7 | 669.0 | ||||||||
| Operating Segments [Member] | Electric Utility Segment [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Operating revenues | 2,502.2 | 2,568.2 | 2,446.3 | ||||||||
| Depreciation and amortization | (330.4) | (306.0) | (289.7) | ||||||||
| Interest (charges) income | (190.9) | (183.0) | (190.5) | ||||||||
| Income tax (expense) benefit | (120.8) | (125.6) | (135.4) | ||||||||
| Net income (loss) | 223.8 | 243.5 | 257.1 | ||||||||
| Assets, Total | 11,045.5 | 10,727.7 | 11,045.5 | 10,727.7 | 9,998.9 | ||||||
| Capital expenditures | 677.1 | 773.7 | 669.0 | ||||||||
| Other [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Operating revenues | 0.0 | 0.0 | 0.0 | ||||||||
| Depreciation and amortization | 0.0 | 0.0 | 0.0 | ||||||||
| Interest (charges) income | (40.5) | (41.2) | (55.5) | ||||||||
| Income tax (expense) benefit | (1.9) | 9.9 | 6.2 | ||||||||
| Net income (loss) | (10.8) | (0.7) | (6.9) | ||||||||
| Assets, Total | (51.1) | 29.2 | (51.1) | 29.2 | 101.1 | ||||||
| Capital expenditures | 0.0 | 0.0 | 0.0 | ||||||||
| Eliminations [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Operating revenues | 0.0 | 0.0 | 0.0 | ||||||||
| Depreciation and amortization | 0.0 | 0.0 | 0.0 | ||||||||
| Interest (charges) income | 32.1 | 35.7 | 47.6 | ||||||||
| Income tax (expense) benefit | 0.0 | 0.0 | 0.0 | ||||||||
| Net income (loss) | 0.0 | 0.0 | 0.0 | ||||||||
| Assets, Total | $ (255.8) | $ (303.5) | (255.8) | (303.5) | (329.8) | ||||||
| Capital expenditures | $ 0.0 | $ 0.0 | $ 0.0 | ||||||||
| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The aggregate revenue, whether regulated or unregulated, derived from the generation, transmission and distribution of electricity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of the cost of borrowed funds accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Jointly Owned Electric Utility Plants (Details) $ in Millions |
Dec. 31, 2015
USD ($)
MW
|
Dec. 31, 2014
USD ($)
|
|---|---|---|
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Nuclear fuel, net | $ 68.3 | $ 79.2 |
| Jeffrey Energy Center [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 8.00% | |
| Utility plant in service | $ 192.9 | |
| Accumulated depreciation | 78.1 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 2.9 | |
| Accredited capacity | MW | 172 | |
| Iatan Common [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 79.00% | |
| Utility plant in service | $ 470.0 | |
| Accumulated depreciation | 112.8 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 35.2 | |
| Iatan No. 2 [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 73.00% | |
| Utility plant in service | $ 1,326.9 | |
| Accumulated depreciation | 365.5 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 20.5 | |
| Accredited capacity | MW | 641 | |
| Iatan No. 1 [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 88.00% | |
| Utility plant in service | $ 667.7 | |
| Accumulated depreciation | 257.6 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 3.3 | |
| Accredited capacity | MW | 627 | |
| LaCygne Station [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 50.00% | |
| Utility plant in service | $ 1,061.1 | |
| Accumulated depreciation | 264.0 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 38.4 | |
| Accredited capacity | MW | 699 | |
| Wolf Creek [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 47.00% | |
| Utility plant in service | $ 1,809.1 | |
| Accumulated depreciation | 862.6 | |
| Nuclear fuel, net | 68.3 | |
| Construction work in progress | $ 74.3 | |
| Accredited capacity | MW | 549 | |
| Kansas City Power and Light Company [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Nuclear fuel, net | $ 68.3 | $ 79.2 |
| Kansas City Power and Light Company [Member] | Iatan Common [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 61.00% | |
| Utility plant in service | $ 385.1 | |
| Accumulated depreciation | 101.4 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 8.6 | |
| Kansas City Power and Light Company [Member] | Iatan No. 2 [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 55.00% | |
| Utility plant in service | $ 1,015.1 | |
| Accumulated depreciation | 331.0 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 8.6 | |
| Accredited capacity | MW | 482 | |
| Kansas City Power and Light Company [Member] | Iatan No. 1 [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 70.00% | |
| Utility plant in service | $ 531.7 | |
| Accumulated depreciation | 209.0 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 1.2 | |
| Accredited capacity | MW | 499 | |
| Kansas City Power and Light Company [Member] | LaCygne Station [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 50.00% | |
| Utility plant in service | $ 1,061.1 | |
| Accumulated depreciation | 264.0 | |
| Nuclear fuel, net | 0.0 | |
| Construction work in progress | $ 38.4 | |
| Accredited capacity | MW | 699 | |
| Kansas City Power and Light Company [Member] | Wolf Creek [Member] | ||
| Jointly Owned Utility Plant Interests [Line Items] | ||
| Jointly Owned Utility Plant, Proportionate Ownership Share | 47.00% | |
| Utility plant in service | $ 1,809.1 | |
| Accumulated depreciation | 862.6 | |
| Nuclear fuel, net | 68.3 | |
| Construction work in progress | $ 74.3 | |
| Accredited capacity | MW | 549 |
| X | ||||||||||
- Definition The accredited capacity of the jointly owned electric utility plant, in megawatts. No definition available.
|
| X | ||||||||||
- Definition The period end amount owned by the reporting utility of a jointly owned utility plant in service. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition The period end amount of construction work in progress at a jointly owned electricity generation plant. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The period end amount of accumulated depreciation in a jointly owned electricity generation plant. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The proportionate share of interest (percent) in a jointly owned utility plant. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The carrying amount as of the balance sheet of nuclear fuel held as property plant and equipment. This amount is net of amortization based on the energy produced over the life of the fuel. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Quarterly Operating Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Operating revenues | $ 562.7 | $ 781.4 | $ 609.0 | $ 549.1 | $ 552.2 | $ 782.5 | $ 648.4 | $ 585.1 | $ 2,502.2 | $ 2,568.2 | $ 2,446.3 |
| Operating income (loss) | 83.4 | 256.7 | 119.9 | 70.1 | 69.2 | 263.2 | 124.2 | 77.9 | $ 530.1 | $ 534.5 | $ 569.2 |
| Net income (loss) | $ 22.9 | $ 126.8 | $ 44.4 | $ 18.9 | $ 19.5 | $ 147.4 | $ 52.1 | $ 23.8 | |||
| Earnings Per Share, Basic and Diluted | $ 0.15 | $ 0.82 | $ 0.28 | $ 0.12 | $ 1.37 | $ 1.57 | $ 1.62 | ||||
| Earnings Per Share, Basic | $ 0.12 | $ 0.96 | $ 0.34 | $ 0.15 | |||||||
| Earnings Per Share, Diluted | $ 0.12 | $ 0.95 | $ 0.34 | $ 0.15 | |||||||
| Kansas City Power and Light Company [Member] | |||||||||||
| Operating revenues | $ 399.7 | $ 526.3 | $ 417.4 | $ 370.4 | $ 366.9 | $ 533.4 | $ 439.5 | $ 391.0 | $ 1,713.8 | $ 1,730.8 | $ 1,671.4 |
| Operating income (loss) | 68.6 | 170.8 | 79.3 | 45.3 | 47.2 | 177.2 | 78.2 | 47.5 | $ 364.0 | $ 350.1 | $ 362.5 |
| Net income (loss) | $ 25.9 | $ 84.3 | $ 29.4 | $ 13.2 | $ 15.9 | $ 94.5 | $ 34.8 | $ 17.2 | |||
| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. No definition available.
|
| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The aggregate revenue, whether regulated or unregulated, derived from the generation, transmission and distribution of electricity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
|
| X | ||||||||||
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Schedule I Financial Statements of Parent Company Statements of Income & OCI (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|||||
| Operating Expenses | |||||||||||||||
| General and administrative | $ 5.9 | $ 4.0 | $ 3.0 | ||||||||||||
| General taxes | 213.2 | 204.6 | 194.4 | ||||||||||||
| Operating Income (Loss) | $ 83.4 | $ 256.7 | $ 119.9 | $ 70.1 | $ 69.2 | $ 263.2 | $ 124.2 | $ 77.9 | 530.1 | 534.5 | 569.2 | ||||
| Equity in earnings (loss) from Subsidiaries | 1.2 | 0.0 | (0.2) | ||||||||||||
| Interest charges | (199.3) | (188.5) | (198.4) | ||||||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | 334.5 | 358.5 | 379.6 | ||||||||||||
| Income tax (expense) benefit | (122.7) | (115.7) | (129.2) | ||||||||||||
| Net income (loss) | $ 22.9 | $ 126.8 | $ 44.4 | $ 18.9 | $ 19.5 | $ 147.4 | $ 52.1 | $ 23.8 | |||||||
| Preferred stock dividend requirements | 1.6 | 1.6 | 1.6 | ||||||||||||
| Earnings (loss) available for common shareholders | $ 211.4 | $ 241.2 | $ 248.6 | ||||||||||||
| Average number of basic common shares outstanding (in shares) | 154.2 | 153.9 | 153.5 | ||||||||||||
| Average number of diluted common shares outstanding (in shares) | 154.8 | 154.1 | 153.7 | ||||||||||||
| Basic Earnings Per Share | $ 0.12 | $ 0.96 | $ 0.34 | $ 0.15 | |||||||||||
| Earnings Per Share, Diluted | $ 0.12 | $ 0.95 | $ 0.34 | $ 0.15 | |||||||||||
| Basic and diluted earnings per common share | $ 0.15 | $ 0.82 | $ 0.28 | $ 0.12 | $ 1.37 | $ 1.57 | $ 1.62 | ||||||||
| Common Stock, Dividends, Per Share, Declared | $ 0.9975 | $ 0.935 | $ 0.8825 | ||||||||||||
| Comprehensive Income | |||||||||||||||
| Net income (loss) | $ 22.9 | $ 126.8 | $ 44.4 | $ 18.9 | $ 19.5 | $ 147.4 | $ 52.1 | $ 23.8 | |||||||
| Other comprehensive income | |||||||||||||||
| Reclassification to expenses, net of tax | $ 5.7 | $ 8.0 | $ 11.6 | ||||||||||||
| Derivative hedging activity, net of tax | 5.7 | 8.0 | 11.6 | ||||||||||||
| Total other comprehensive income (loss) | 6.7 | [1] | 6.6 | [1] | 13.1 | ||||||||||
| Comprehensive income (loss) | 219.7 | 249.4 | 263.3 | ||||||||||||
| Parent Company [Member] | |||||||||||||||
| Operating Expenses | |||||||||||||||
| General and administrative | 0.9 | 1.1 | 1.0 | ||||||||||||
| General taxes | 0.2 | 0.4 | 0.6 | ||||||||||||
| Operating Expenses | 1.1 | 1.5 | 1.6 | ||||||||||||
| Operating Income (Loss) | (1.1) | (1.5) | (1.6) | ||||||||||||
| Equity in earnings (loss) from Subsidiaries | 220.9 | 251.1 | 256.5 | ||||||||||||
| Non-operating income | 29.7 | 33.1 | 45.8 | ||||||||||||
| Interest charges | (40.3) | (44.3) | (54.7) | ||||||||||||
| Income before income tax (expense) benefit and income (loss) from equity investments | 209.2 | 238.4 | 246.0 | ||||||||||||
| Income tax (expense) benefit | 3.8 | 4.4 | 4.2 | ||||||||||||
| Net income (loss) | 213.0 | 242.8 | 250.2 | ||||||||||||
| Preferred stock dividend requirements | 1.6 | 1.6 | 1.6 | ||||||||||||
| Earnings (loss) available for common shareholders | $ 211.4 | $ 241.2 | $ 248.6 | ||||||||||||
| Average number of basic common shares outstanding (in shares) | 154.2 | 153.9 | 153.5 | ||||||||||||
| Average number of diluted common shares outstanding (in shares) | 154.8 | 154.1 | 153.7 | ||||||||||||
| Basic and diluted earnings per common share | $ 1.37 | $ 1.57 | $ 1.62 | ||||||||||||
| Comprehensive Income | |||||||||||||||
| Net income (loss) | $ 213.0 | $ 242.8 | $ 250.2 | ||||||||||||
| Other comprehensive income | |||||||||||||||
| Reclassification to expenses | 0.5 | 4.4 | 9.9 | ||||||||||||
| Income tax (expense) benefit on reclassification to expenses | (0.1) | (1.7) | (3.9) | ||||||||||||
| Reclassification to expenses, net of tax | 0.4 | 2.7 | 6.0 | ||||||||||||
| Derivative hedging activity, net of tax | 0.4 | 2.7 | 6.0 | ||||||||||||
| Other comprehensive income from subsidiaries, net of tax | 6.3 | 3.9 | 7.1 | ||||||||||||
| Total other comprehensive income (loss) | 6.7 | 6.6 | 13.1 | ||||||||||||
| Comprehensive income (loss) | $ 219.7 | $ 249.4 | $ 263.3 | ||||||||||||
| |||||||||||||||
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- Definition Other comprehensive income from subsidiaries, net of tax No definition available.
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- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- References No definition available.
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. No definition available.
|
| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of the cost of borrowed funds accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. No definition available.
|
| X | ||||||||||
- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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| X | ||||||||||
- Definition Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount before tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The sum of expenses not otherwise specified in the taxonomy for managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate amount of other income amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders. No definition available.
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| X | ||||||||||
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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Schedule I Financial Statements of Parent Company Balance Sheet (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|||||
|---|---|---|---|---|---|---|---|---|
| Current Assets | ||||||||
| Taxes receivable | $ 3.8 | $ 3.1 | ||||||
| Assets, Current, Total | 664.2 | 718.9 | ||||||
| Investments and Other Assets | ||||||||
| Other Assets, Noncurrent | 63.2 | 52.3 | ||||||
| Assets, Total | 10,738.6 | 10,453.4 | $ 9,770.2 | |||||
| Current Liabilities | ||||||||
| Notes payable | 10.0 | 4.0 | ||||||
| Current maturities of long-term debt | 1.1 | 15.1 | ||||||
| Accrued taxes | 31.6 | 30.4 | ||||||
| Accrued interest | 44.7 | 41.3 | ||||||
| Other Liabilities, Current | 31.6 | 24.7 | ||||||
| Liabilities, Current, Total | 915.7 | 1,070.8 | ||||||
| Deferred Credits and Other Liabilities | ||||||||
| Liabilities, Noncurrent, Total | 2,382.3 | 2,291.8 | ||||||
| Capitalization | ||||||||
| Common Stock, Value, Issued | 2,646.7 | 2,639.3 | ||||||
| Retained earnings | 1,024.4 | 967.8 | ||||||
| Treasury Stock, Value | (2.6) | (2.3) | ||||||
| Accumulated Other Comprehensive Income (Loss), Net of Tax | [1] | (12.0) | (18.7) | (25.3) | ||||
| Common Shareholders' Equity, Total | 3,656.5 | 3,586.1 | $ 3,474.4 | |||||
| Preferred Stock, Value, Issued | 39.0 | 39.0 | ||||||
| Long-term debt | [2] | 3,745.1 | 3,465.7 | |||||
| Total Capitalization | $ 7,440.6 | $ 7,090.8 | ||||||
| Commitments and Contingencies | ||||||||
| Liabilities and Equity, Total | $ 10,738.6 | $ 10,453.4 | ||||||
| Parent Company [Member] | ||||||||
| Current Assets | ||||||||
| Accounts receivable from subsidiaries | 4.1 | 4.0 | ||||||
| Notes receivable from subsidiaries, current | 2.0 | 0.6 | ||||||
| Money pool receivable | 3.7 | 3.3 | ||||||
| Other current assets | 0.4 | 1.0 | ||||||
| Assets, Current, Total | 10.2 | 8.9 | ||||||
| Investments and Other Assets | ||||||||
| Investment in KCP&L | 2,433.1 | 2,275.0 | ||||||
| Investment in other subsidiaries | 1,385.9 | 1,465.9 | ||||||
| Notes receivable from subsidiaries, noncurrent | 634.9 | 634.9 | ||||||
| Deferred income taxes | 34.8 | 32.8 | ||||||
| Other Assets, Noncurrent | 1.6 | 2.0 | ||||||
| Total investments and other assets | 4,490.3 | 4,410.6 | ||||||
| Assets, Total | 4,500.5 | 4,419.5 | ||||||
| Current Liabilities | ||||||||
| Notes payable | 10.0 | 4.0 | ||||||
| Accounts payable to subsidiaries | 31.7 | 30.4 | ||||||
| Accrued taxes | 4.5 | 4.3 | ||||||
| Accrued interest | 4.1 | 4.1 | ||||||
| Other Liabilities, Current | 9.5 | 2.2 | ||||||
| Liabilities, Current, Total | 59.8 | 45.0 | ||||||
| Deferred Credits and Other Liabilities | ||||||||
| Liabilities, Noncurrent, Total | 7.1 | 11.4 | ||||||
| Capitalization | ||||||||
| Common Stock, Value, Issued | 2,646.7 | 2,639.3 | ||||||
| Retained earnings | 1,024.4 | 967.8 | ||||||
| Treasury Stock, Value | (2.6) | (2.3) | ||||||
| Accumulated Other Comprehensive Income (Loss), Net of Tax | (12.0) | (18.7) | ||||||
| Common Shareholders' Equity, Total | 3,656.5 | 3,586.1 | ||||||
| Preferred Stock, Value, Issued | 39.0 | 39.0 | ||||||
| Long-term debt | 738.1 | 738.0 | ||||||
| Total Capitalization | $ 4,433.6 | $ 4,363.1 | ||||||
| Commitments and Contingencies | ||||||||
| Liabilities and Equity, Total | $ 4,500.5 | $ 4,419.5 | ||||||
| Preferred Stock 3 Point 80 [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 10.0 | 10.0 | ||||||
| Preferred Stock 3 Point 80 [Member] | Parent Company [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 10.0 | 10.0 | ||||||
| Preferred Stock 4 Point 50 [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 10.0 | 10.0 | ||||||
| Preferred Stock 4 Point 50 [Member] | Parent Company [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 10.0 | 10.0 | ||||||
| Preferred Stock 4 Point 20 [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 7.0 | 7.0 | ||||||
| Preferred Stock 4 Point 20 [Member] | Parent Company [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 7.0 | 7.0 | ||||||
| Preferred Stock 4 Point 35 [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | 12.0 | 12.0 | ||||||
| Preferred Stock 4 Point 35 [Member] | Parent Company [Member] | ||||||||
| Capitalization | ||||||||
| Preferred Stock, Value, Issued | $ 12.0 | $ 12.0 | ||||||
| ||||||||
| X | ||||||||||
- Definition This item represents the carrying amount of Great Plains Energy's investment in KCPL, its other reporting consolidated subsidiary, presented as an equity method investment for stand-alone presentation of the parent company. No definition available.
|
| X | ||||||||||
- Definition This item represents the carrying amount of Great Plains Energy's investments in other subsidiaries (other than KCPL) presented as equity method investments for stand-alond reporting of the parent company. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount receivable under the Great Plains Energy money pool, an internal financing arrangement. No definition available.
|
| X | ||||||||||
- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This element represents the total consolidated (as applicable) capitalization of the entity which is comprised of its long-term debt and equity instruments. The table may be detailed by subsidiary (legal entity) and include information by type of debt or equity detailed by instrument. No definition available.
|
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, netted by jurisdiction and classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of obligation due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amounts due from parties associated with the reporting entity as evidenced by a written promise to pay, due within 1 year (or 1 business cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amounts due from parties associated with the reporting entity as evidenced by a written promise to pay, due after 1 year (or 1 business cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Aggregate carrying amount, as of the balance sheet date, of current assets not separately disclosed in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Aggregate carrying amount of current liabilities (due within one year or within the normal operating cycle if longer) not separately disclosed in the balance sheet. Includes costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered and of liabilities not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount at the balance sheet date of borrowings from a bank, not elsewhere enumerated in the taxonomy, with a maturity within one year (or within one operating cycle if longer) from the date of borrowing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying value as of the balance sheet date of obligations incurred and payable for statutory income, sales, use, payroll, excise, real, property and other taxes. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Schedule I Financial Statements of Parent Company Balance Sheet Parenthetical (Details) - $ / shares |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Common Stock, Shares Authorized | 250,000,000 | 250,000,000 |
| Common Stock, Shares, Issued | 154,504,900 | 154,254,037 |
| Treasury Stock, Shares | 101,229 | 91,281 |
| Parent Company [Member] | ||
| Common Stock, Shares Authorized | 250,000,000 | 250,000,000 |
| Common Stock, Shares, Issued | 154,504,900 | 154,254,037 |
| Treasury Stock, Shares | 101,229 | 91,281 |
| Preferred Stock 3 Point 80 [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 3.80% | 3.80% |
| Preferred Stock, Shares Issued | 100,000 | 100,000 |
| Preferred Stock 3 Point 80 [Member] | Parent Company [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 3.80% | 3.80% |
| Preferred Stock, Shares Issued | 100,000 | 100,000 |
| Preferred Stock 4 Point 50 [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 4.50% | 4.50% |
| Preferred Stock, Shares Issued | 100,000 | 100,000 |
| Preferred Stock 4 Point 50 [Member] | Parent Company [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 4.50% | 4.50% |
| Preferred Stock, Shares Issued | 100,000 | 100,000 |
| Preferred Stock 4 Point 20 [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 4.20% | 4.20% |
| Preferred Stock, Shares Issued | 70,000 | 70,000 |
| Preferred Stock 4 Point 20 [Member] | Parent Company [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 4.20% | 4.20% |
| Preferred Stock, Shares Issued | 70,000 | 70,000 |
| Preferred Stock 4 Point 35 [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 4.35% | 4.35% |
| Preferred Stock, Shares Issued | 120,000 | 120,000 |
| Preferred Stock 4 Point 35 [Member] | Parent Company [Member] | ||
| Preferred Stock, Par or Stated Value Per Share | $ 100.00 | $ 100.00 |
| Preferred Stock, Dividend Rate, Percentage | 4.35% | 4.35% |
| Preferred Stock, Shares Issued | 120,000 | 120,000 |
| X | ||||||||||
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The percentage rate used to calculate dividend payments on preferred stock. No definition available.
|
| X | ||||||||||
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Schedule I Financial Statements of Parent Company Statement of Cash Flows (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Cash Flows from Operating Activities | |||||||||||
| Net income (loss) | $ 22.9 | $ 126.8 | $ 44.4 | $ 18.9 | $ 19.5 | $ 147.4 | $ 52.1 | $ 23.8 | |||
| Adjustments to reconcile income to net cash from operating activities: | |||||||||||
| Deferred income taxes, net | $ 124.9 | $ 125.8 | $ 134.0 | ||||||||
| Equity in earnings from subsidiaries | (1.2) | 0.0 | 0.2 | ||||||||
| Cash flows affected by changes in: | |||||||||||
| Accrued taxes | 1.1 | 8.3 | 2.2 | ||||||||
| Accrued interest | 3.4 | (4.1) | 3.9 | ||||||||
| Other operating activities | (2.9) | (12.3) | 16.2 | ||||||||
| Net cash from operating activities | 753.1 | 698.2 | 776.8 | ||||||||
| Cash Flows from Investing Activities | |||||||||||
| Other investing activities | (48.2) | (27.5) | (21.7) | ||||||||
| Net cash from investing activities | (734.4) | (779.8) | (705.8) | ||||||||
| Cash Flows from Financing Activities | |||||||||||
| Issuance of common stock | 3.0 | 4.8 | 4.9 | ||||||||
| Issuance of long-term debt | 348.8 | 0.0 | 762.5 | ||||||||
| Issuance fees | (3.0) | (0.9) | (9.0) | ||||||||
| Repayment of long-term debt | (87.0) | (13.4) | (265.3) | ||||||||
| Net change in short-term borrowings | (128.3) | 245.1 | (424.9) | ||||||||
| Dividends paid | (155.5) | (145.6) | (137.3) | ||||||||
| Other financing activities | (2.4) | (2.0) | (1.6) | ||||||||
| Net cash from financing activities | (20.4) | 84.0 | (69.7) | ||||||||
| Net Change in Cash and Cash Equivalents | (1.7) | 2.4 | 1.3 | ||||||||
| Cash and Cash Equivalents at Beginning of Year | 13.0 | 10.6 | 13.0 | 10.6 | 9.3 | ||||||
| Cash and Cash Equivalents at End of Year | 11.3 | 13.0 | 11.3 | 13.0 | 10.6 | ||||||
| Parent Company [Member] | |||||||||||
| Cash Flows from Operating Activities | |||||||||||
| Net income (loss) | 213.0 | 242.8 | 250.2 | ||||||||
| Adjustments to reconcile income to net cash from operating activities: | |||||||||||
| Amortization | 0.8 | 4.8 | 10.6 | ||||||||
| Deferred income taxes, net | (1.7) | (1.4) | (10.5) | ||||||||
| Equity in earnings from subsidiaries | (220.9) | (251.1) | (256.5) | ||||||||
| Cash flows affected by changes in: | |||||||||||
| Accounts receivable from subsidiaries | (0.1) | (3.8) | (0.1) | ||||||||
| Taxes receivable | 0.0 | 0.2 | (0.2) | ||||||||
| Accounts payable to subsidiaries | 1.3 | (3.2) | (0.5) | ||||||||
| Other accounts payable | 0.0 | 0.0 | 0.1 | ||||||||
| Accrued taxes | 0.3 | 4.3 | (0.1) | ||||||||
| Accrued interest | 0.0 | (0.1) | (2.6) | ||||||||
| Cash dividends from subsidiaries | 157.0 | 144.0 | 140.0 | ||||||||
| Uncertain tax positions | 0.0 | (2.9) | 7.3 | ||||||||
| Other operating activities | 8.7 | 11.8 | 6.8 | ||||||||
| Net cash from operating activities | 158.4 | 145.4 | 144.5 | ||||||||
| Cash Flows from Investing Activities | |||||||||||
| Intercompany lending | (1.4) | 0.0 | 248.7 | ||||||||
| Net money pool lending | (0.4) | 6.1 | (5.4) | ||||||||
| Investment in subsidiary | (7.8) | (3.6) | (0.5) | ||||||||
| Net cash from investing activities | (9.6) | 2.5 | 242.8 | ||||||||
| Cash Flows from Financing Activities | |||||||||||
| Issuance of common stock | 3.0 | 4.8 | 4.9 | ||||||||
| Issuance fees | 0.0 | (0.1) | (0.4) | ||||||||
| Repayment of long-term debt | 0.0 | 0.0 | (250.0) | ||||||||
| Net change in short-term borrowings | 6.0 | (5.0) | (3.0) | ||||||||
| Dividends paid | (155.5) | (145.6) | (137.3) | ||||||||
| Other financing activities | (2.3) | (2.0) | (1.5) | ||||||||
| Net cash from financing activities | (148.8) | (147.9) | (387.3) | ||||||||
| Net Change in Cash and Cash Equivalents | 0.0 | 0.0 | 0.0 | ||||||||
| Cash and Cash Equivalents at Beginning of Year | $ 0.0 | $ 0.0 | 0.0 | 0.0 | 0.0 | ||||||
| Cash and Cash Equivalents at End of Year | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 | ||||||
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the value of uncertain tax positions. No definition available.
|
| X | ||||||||||
- Definition Cash outflows (inflows) from intercompany lending. No definition available.
|
| X | ||||||||||
- Definition The net cash outflows or inflows in money pool lending. No definition available.
|
| X | ||||||||||
- Definition The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This element represents disclosure of the aggregate cash dividends paid to the entity by consolidated subsidiaries. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period of all taxes owed but not paid, including income, property and other taxes. No definition available.
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in receivables to be collected from other entities that could exert significant influence over the reporting entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the aggregate amount of obligations to be paid to the following types of related parties: a parent company and its subsidiaries; subsidiaries of a common parent; an entity and trust for the benefit of employees, such as pension and profit-sharing trusts that are managed by or under the trusteeship of the entities' management; an entity and its principal owners, management, or member of their immediate families; affiliates; or other parties with the ability to exert significant influence. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in income taxes receivable, which represents the amount due from tax authorities for refunds of overpayments or recoveries of income taxes paid. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in other obligations or expenses incurred but not yet paid. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Other cash or noncash adjustments to reconcile net income to cash provided by (used in) operating activities that are not separately disclosed in the statement of cash flows (for example, cash received or cash paid during the current period for miscellaneous operating activities, net change during the reporting period in other assets or other liabilities). No definition available.
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| X | ||||||||||
- Definition The total of the cash outflow during the period which has been paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt and the cost incurred directly for the issuance of equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net cash outflow or inflow from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash inflow from the additional capital contribution to the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow for borrowing having initial term of repayment within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions |
12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
||||||||||
| Allowance for Doubtful Accounts [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | $ 2.8 | $ 2.5 | $ 6.9 | |||||||||
| Additions charged to costs and expenses | 10.5 | 11.4 | 12.3 | |||||||||
| Additions charged to other accounts | [1] | 8.7 | 8.5 | 7.6 | ||||||||
| Deductions | [2] | 18.2 | 19.6 | 24.3 | ||||||||
| Balance at end of period | 3.8 | 2.8 | 2.5 | |||||||||
| Allowance for Doubtful Accounts [Member] | Kansas City Power and Light Company [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 1.2 | 1.1 | 1.5 | |||||||||
| Additions charged to costs and expenses | 7.1 | 7.6 | 8.0 | |||||||||
| Additions charged to other accounts | [1] | 5.8 | 5.5 | 5.0 | ||||||||
| Deductions | [2] | 12.3 | 13.0 | 13.4 | ||||||||
| Balance at end of period | 1.8 | 1.2 | 1.1 | |||||||||
| Legal Reserve [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 4.7 | 4.6 | 4.6 | |||||||||
| Additions charged to costs and expenses | 2.6 | 2.7 | 2.7 | |||||||||
| Additions charged to other accounts | 0.0 | 0.0 | 0.0 | |||||||||
| Deductions | [3] | 1.4 | 2.6 | 2.7 | ||||||||
| Balance at end of period | 5.9 | 4.7 | 4.6 | |||||||||
| Legal Reserve [Member] | Kansas City Power and Light Company [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 2.9 | 2.9 | 2.9 | |||||||||
| Additions charged to costs and expenses | 2.6 | 2.3 | 0.9 | |||||||||
| Additions charged to other accounts | 0.0 | 0.0 | 0.0 | |||||||||
| Deductions | [3] | 0.2 | 2.3 | 0.9 | ||||||||
| Balance at end of period | 5.3 | 2.9 | 2.9 | |||||||||
| Reserve for Environmental Costs [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 1.7 | 1.7 | 2.3 | |||||||||
| Additions charged to costs and expenses | 0.0 | 0.0 | 0.0 | |||||||||
| Additions charged to other accounts | 0.0 | 0.0 | 0.0 | |||||||||
| Deductions | 0.0 | 0.0 | 0.6 | |||||||||
| Balance at end of period | 1.7 | 1.7 | 1.7 | |||||||||
| Reserve for Environmental Costs [Member] | Kansas City Power and Light Company [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 0.3 | 0.3 | 0.3 | |||||||||
| Additions charged to costs and expenses | 0.0 | 0.0 | 0.0 | |||||||||
| Additions charged to other accounts | 0.0 | 0.0 | 0.0 | |||||||||
| Deductions | 0.0 | 0.0 | 0.0 | |||||||||
| Balance at end of period | 0.3 | 0.3 | 0.3 | |||||||||
| Valuation Allowance of Deferred Tax Assets [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 16.6 | 20.7 | 23.8 | |||||||||
| Additions charged to costs and expenses | 4.9 | 0.5 | 0.1 | |||||||||
| Additions charged to other accounts | 0.0 | 0.0 | 0.0 | |||||||||
| Deductions | [4] | 1.6 | 4.6 | 3.2 | ||||||||
| Balance at end of period | 19.9 | 16.6 | $ 20.7 | |||||||||
| Valuation Allowance of Deferred Tax Assets [Member] | Kansas City Power and Light Company [Member] | ||||||||||||
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||||||||||||
| Balance at beginning of period | 0.0 | |||||||||||
| Additions charged to costs and expenses | 0.7 | |||||||||||
| Additions charged to other accounts | 0.0 | |||||||||||
| Deductions | 0.0 | |||||||||||
| Balance at end of period | $ 0.7 | $ 0.0 | ||||||||||
| ||||||||||||
| X | ||||||||||
- Definition Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, charged to costs and expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, charged to accounts other than costs and expenses in a given period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
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