v3.7.0.1
Document and Entity Information Document - shares
3 Months Ended
Mar. 31, 2017
May 03, 2017
Entity Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q1  
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   142,093,321