Fair Value of Financial Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 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 in the consolidated statements of common stockholder's equity and in the consolidated statements of comprehensive income, is detailed in the following table:

(Thousands of Dollars)	2012			2011			2010
Accumulated other comprehensive loss related to cash flow hedges at Jan. 1	$	(514	)	$	(590	)	$	(666	)
After-tax net realized losses on derivative transactions reclassified into earnings		77			76			76
Accumulated other comprehensive loss related to cash flow hedges at Dec. 31	$	(437	)	$	(514	)	$	(590	)

Gross Notional Amounts of Commodity Forwards and Options

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

(Amounts in Thousands) (a) (b)	Dec. 31, 2012		Dec. 31, 2011
MMBtu of natural gas		53		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 Assets and Liabilities Measured at Fair Value on a Recurring Basis by Hierarchy Level

	Dec. 31, 2012
	Fair Value
							Fair Value		Counterparty
(Thousands of Dollars)	Level 1		Level 2		Level 3		Total		Netting (a)		Total (b)
Current derivative liabilities
Natural gas commodity	$	-	$	11	$	-	$	11	$	-	$	11

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

(a) The accounting guidance for derivatives and hedging permits the netting of receivables and payables for derivatives and related collateral amounts when a legally enforceable master netting agreement exists between NSP-Wisconsin and a counterparty. A master netting agreement is an agreement between two parties who have multiple contracts with each other that provides for the net settlement of all contracts in the event of default on or termination of any one contract.

(b) Included in other current liabilities balance of $11.8 million and $13.9 million at Dec. 31, 2012 and 2011, respectively, in the consolidated balance sheets.

Carrying Amount and Fair Value of Long-term Debt

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

	2012				2011
(Thousands of Dollars)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-term debt, including current portion	$	468,563	$	576,353	$	369,369	$	474,356