Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Jun. 30, 2013
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The significant accounting policies set forth in Note 1 to the consolidated financial statements in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2012, appropriately represent, in all material respects, the current status of accounting policies and are incorporated herein by reference. The electric production and transmission system of NSP-Minnesota and NSP-Wisconsin (NSP System) is operated on an integrated basis and managed by NSP-Minnesota. The electric production and transmission costs of the NSP System are shared by NSP-Minnesota and NSP-Wisconsin. A Federal Energy Regulatory Commission (FERC) approved Interchange Agreement between the two companies provides for the sharing of all generation and transmission costs of the NSP System. Such costs include current and potential obligations of NSP-Minnesota related to its nuclear generating facilities.

The entire disclosure for all significant accounting policies of the reporting entity.