v2.4.0.6
Document And Entity Information (USD $)
9 Months Ended
Sep. 30, 2011
Oct. 31, 2011
Jun. 30, 2010
Entity 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     $ 2,307,217,754
Entity Common Stock, Shares Outstanding   136,087,321  
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q3    
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Sep. 30, 2011    
KANSAS CITY POWER AND LIGHT CO [Member]
     
Entity Information [Line Items]      
Entity Registrant Name Kansas City Power & Light Co    
Entity Central Index Key 0000054476    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Non-accelerated Filer    
Entity Public Float     $ 0
Entity Common Stock, Shares Outstanding   1  
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q3    
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Sep. 30, 2011