Document and Entity Information Document (USD $) In Billions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014
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, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding	225,517,341
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$ 10.6