v3.5.0.2
Document and Entity Information Document - shares
6 Months Ended
Jun. 30, 2016
Jul. 27, 2016
Entity Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q2  
Trading Symbol WR  
Entity Registrant Name WESTAR ENERGY INC /KS  
Entity Central Index Key 0000054507  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   141,734,848