DISPOSITIONS - DISPOSITIONS EXCLUDING DISCONTINUED OPERATIONS (Details) (USD $) In Millions, unless otherwise specified		1 Months Ended				1 Months Ended
	May 31, 2014 Integrys Energy Services IES retail energy business	Jul. 31, 2014 Integrys Energy Services IES retail energy business Subsequent event	Jan. 31, 2014 Electric Utility UPPCO	Jun. 30, 2014 Electric Utility UPPCO	Dec. 31, 2013 Electric Utility UPPCO	Jan. 31, 2014 Electric Utility UPPCO Minimum	Jan. 31, 2014 Electric Utility UPPCO Maximum
Disclosures related to the disposal
Expected proceeds from sale		$ 60.0	$ 298.8
Net working capital	183
Transition period for services		15 months				18 months	30 months
Intercompany payables included in sale				2.2	1.6
Assets and liabilities classified as held for sale on balance sheets
Current assets				24.6	26.5
Property, plant, and equipment, net of accumulated depreciation of $90.5 and $88.9, respectively				193.3	193.8
Accumulated depreciation				90.5	88.9
Other long-term assets				71.8	51.6
Total assets				289.7	271.9
Current liabilities				13.8	16.7
Long-term liabilities				29.2	32.4
Total liabilities				$ 43.0	$ 49.1