Rate Matters Rate Matters (Details) (USD $)	1 Months Ended
	May 31, 2014 Electric Rate Case 2015 [Member] Public Service Commission of Wisconsin (PSCW) [Member]	May 31, 2014 Natural Gas Rate Case 2014 [Member] Michigan Public Service Commission (MPSC) [Member]	Dec. 31, 2013 Natural Gas Rate Case 2014 [Member] Michigan Public Service Commission (MPSC) [Member]	Jun. 30, 2014 FERC Proceeding, MISO ROE Complaint [Member] Federal Energy Regulatory Commission (FERC) [Member]	Jan. 31, 2014 FERC Proceeding, MISO ROE Complaint [Member] Federal Energy Regulatory Commission (FERC) [Member]	Nov. 30, 2013 FERC Proceeding, MISO ROE Complaint [Member] Federal Energy Regulatory Commission (FERC) [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Percentage	3.20%		8.80%
Public Utilities, Requested Return on Equity, Percentage	10.20%		10.40%
Public Utilities, percentage of earnings above the authorized ROE that will be refunded to customers	100.00%
Public Utilities, amount requested by public utility related to production and transmission fixed charges	$ 28,100,000
Public Utilities, amount requested by public utility related to fuel and purchased power	13,900,000
Public Utilities, requested base revenue increase (decrease) excluding NSP-Minnesota depreciation reserve and Monticello EPU deferral adjustments	42,000,000
Public Utilities, Adjustment to requested rate increase (decrease) related to the NSP-Minnesota transmission depreciation reserve	(16,200,000)
Public Utilities, Adjustment to requested rate increase (decrease) related to the Monticello EPU deferral	(5,200,000)
Public Utilities, Requested Rate Increase (Decrease), Amount	20,600,000		527,000
Public Utilities, Requested Equity Capital Structure, Percentage			52.54%
Public Utilities, Requested Rate Base, Amount			4,700,000
Public Utilities, Approved Rate Increase (Decrease), Amount		500,000
Public Utilities, Approved Rate Increase (Decrease), Percentage		8.40%
Public Utilities, Approved Return on Equity, Percentage		10.20%
Public Utilities, number of years rate case is applicable for		2 years
Public Utilities, ROE applicable to transmission formula rates in the MISO region, upper bound						12.38%
Public Utilities, ROE applicable to transmission formula rates in the MISO region, lower bound					9.15%	9.15%
Public Utilities, maximum equity capital structure percentage allowed per the complaint						50.00%
Public Utilities, number of steps required for newly adopted ROE discounted cash flow methodology				2
Public Utilities, reduction of transmission revenue, net of expense due to the new ROE methodology, lower bound				5,000,000
Public Utilities, reduction of transmission revenue, net of expense due to the new ROE methodology, upper bound				$ 7,000,000