v2.4.0.6
Document and Entity Information (USD $)
12 Months Ended
Dec. 31, 2010
Feb. 15, 2011
Jun. 30, 2010
Document and Entity Information      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2010    
Document Fiscal Year Focus 2010    
Document Fiscal Period Focus FY    
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   113,566,796  
Entity Public Float     $ 2,391,619,392
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Well-known Seasoned Issuer Yes