DOCUMENT AND ENTITY INFORMATION	3 Months Ended
	Mar. 31, 2015	May 04, 2015
Document and Entity Information
Entity Registrant Name	INTEGRYS ENERGY GROUP, INC.
Entity Central Index Key	0000916863
Document Type	10-Q
Document Period End Date	Mar. 31, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		79,963,091
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1