v2.4.0.8
Document and Entity Information Document (USD $)
In Billions, except Share data, unless otherwise specified
9 Months Ended
Sep. 30, 2013
Jun. 30, 2013
Entity Information [Line Items]    
Entity Registrant Name WISCONSIN ENERGY CORP  
Entity Central Index Key 0000783325  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Sep. 30, 2013  
Document Fiscal Year Focus 2013  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Common Stock, Shares Outstanding 226,519,569  
Entity Well-known Seasoned Issuer Yes  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Public Float   $ 9.3