SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES REVENUE AND CUSTOMER RECEIVABLES (Details) (USD $) In Millions, unless otherwise specified				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 WPS	Dec. 31, 2013 Customer concentration risk customer industry
Revenue from external customers
Unbilled revenues	$ 438.2	$ 298.2
Customers that account for more than 10% of revenues				0
Industries that account for more than 10% of revenues				0
Threshold percentage of revenues from major customers or industries				10.00%
Percentage price variance from rate case-approved fuel and purchased power costs before deferral is required			2.00%