VARIABLE INTEREST ENTITIES (Details) (Fox Energy Company LLC, USD $) In Millions, unless otherwise specified	Mar. 31, 2013 MW
Fox Energy Company LLC
Acquisitions
Contract termination fee related to tolling arrangement	$ 50.0
Contracted capacity under a power purchase agreement (in megawatts)	500

Represents the contracted capacity (in megawatts) from a variable interest entity under a power purchase agreement.

No definition available.

Name:	wps_ContractedCapacityFromVariableInterestEntityPowerPurchaseAgreement
Namespace Prefix:	wps_
Data Type:	num:powerItemType
Balance Type:	na
Period Type:	instant