DOCUMENT AND ENTITY INFORMATION	3 Months Ended
	Mar. 31, 2018 shares
Document Entity Information [Abstract]
Entity registrant name	WEC Energy Group, Inc.
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	Mar. 31, 2018
Document fiscal year focus	2018
Document fiscal period focus	Q1
Amendment flag	false
Entity common stock, shares outstanding	315,538,808