Fair Value of Financial Assets and Liabilities (Tables)

9 Months Ended

Sep. 30, 2012

Fair Value of Financial Assets and Liabilities [Abstract]

Financial Impact of Qualifying Cash Flow Hedges on Accumulated Other Comprehensive Loss

Financial Impact of Qualifying Cash Flow Hedges — The impact of qualifying interest rate cash flow hedges on NSP-Wisconsin's accumulated other comprehensive loss, included as a component of common stockholder's equity and in the consolidated statement of comprehensive income, is detailed in the following table:

	Three Months Ended Sept. 30
(Thousands of Dollars)	2012			2011
Accumulated other comprehensive loss related to cash flow hedges at July 1	$	(476	)	$	(552	)
After-tax net realized losses on derivative transactions reclassified into earnings		20			19
Accumulated other comprehensive loss related to cash flow hedges at Sept. 30	$	(456	)	$	(533	)

	Nine Months Ended Sept. 30
(Thousands of Dollars)	2012			2011
Accumulated other comprehensive loss related to cash flow hedges at Jan. 1	$	(514	)		$	(590	)
After-tax net realized losses on derivative transactions reclassified into earnings		58				57
Accumulated other comprehensive loss related to cash flow hedges at Sept. 30	$	(456	)		$	(533	)

Gross Notional Amounts of Commodity Forwards and Options

The following table details the gross notional amounts of commodity forwards and options at Sept. 30, 2012 and Dec. 31, 2011:

(Amounts in Thousands) (a)(b)	Sept. 30, 2012		Dec. 31, 2011
MMBtu of natural gas		328		1,393

(a) Amounts are not reflective of net positions in the underlying commodities.

(b) Notional amounts for options are included on a gross basis, but are weighted for the probability of exercise.

Derivative Liabilities Measured at Fair Value on a Recurring Basis by Hierarchy Level

The following table presents, for each of the hierarchy levels, NSP-Wisconsin's liabilities that are measured at fair value on a recurring basis:

	Dec. 31, 2011
	Fair Value
							Fair Value
(Thousands of Dollars)	Level 1		Level 2		Level 3		Total
Current derivative liabilities
Natural gas commodity	$	418	$	2,096	$	-	$	2,514

Carrying Amount and Fair Value of Long-term Debt

As of Sept. 30, 2012 and Dec. 31, 2011, other financial instruments for which the carrying amount did not equal fair value were as follows:

	Sept. 30, 2012				Dec. 31, 2011
	Carrying				Carrying
(Thousands of Dollars)	Amount		Fair Value		Amount		Fair Value
Long-term debt, including current portion	$	369,403	$	483,430	$	369,369	$	474,356