Common Equity - Integrys Acquisition (Details) shares in Millions	1 Months Ended
Jun. 30, 2015 shares
Common Equity 7 [Abstract]
Wisconsin Energy Shares issued for Integrys shares	90.2

Number of shares of equity interest issued or issuable, number of shares.

No definition available.

Name:	wec_BusinessAcquisitionEquityInterestIssuedorIssuableNumberofShares
Namespace Prefix:	wec_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration