Fair Value: (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value:

Schedule of assets and liabilities measured at fair value on a recurring basis

		Fair Value Measurements at Reporting Date Using
		December 31, 2012			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)	Valuation Technique
		(dollars in thousands)
Nuclear decommissioning trust funds:
Domestic equity	$	118,329		$	118,329	$	–		$	–	(1)
International equity		48,105			48,105		–			–	(1)
Corporate bonds		53,172			–		53,172			–	(1)
U.S. Treasury and government agency securities		46,626			46,626		–			–	(1)
Agency mortgage and asset backed securities		21,273			–		21,273			–	(1)
Other		13,280			13,280		–			–	(1)
Long-term investments:
Corporate bonds		5,762			–		5,762			–	(1)
U.S. Treasury and government agency securities		7,387			7,387		–			–	(1)
Agency mortgage and asset backed securities		2,526			–		2,526			–	(1)
Mutual funds		60,972			60,972		–			–	(1)
Other		375			375		–			–	(1)
Interest rate options		25,783	(1)		–		–			25,783	(3)
Natural gas swaps		(1,085	)		–		(1,085	)		–	(1)

		Fair Value Measurements at Reporting Date Using
		December 31, 2011			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)		Valuation Technique
		(dollars in thousands)
Nuclear Decommissioning trust funds:
Domestic equity	$	102,285		$	102,285	$	–		$	–		(1)
International equity		39,618			39,618		–			–		(1)
Corporate bonds		41,338			–		41,338			–		(1)
U.S. Treasury and government agency securities		41,697			41,697		–			–		(1)
Agency mortgage and asset backed securities		28,519			–		28,519			–		(1)
Derivative instruments		(982	)		–		–			(982	)	(3)
Other		16,122			16,122		–			–		(1)
Long-term investments:												(1)
Mutual funds		75,062			75,062		–			–		(1)
Auction rate securities		7,713			–		–			7,713	(2)	(3)
Interest rate options		69,446	(1)		–		–			69,446		(3)
Natural gas swaps		(7,220	)		–		(7,220	)		–		(1)

(1)

Interest rate options as reflected on the Consolidated Balance Sheet includes the fair value of the interest rate options offset by $8,950,000 and $43,070,000 of collateral received by the counterparties at December 31, 2012 and 2011, respectively.

(2)

Represents auction rate securities investments we held.

Schedule of changes in Level 3 assets and liabilities measured at fair value on a recurring basis

		Year Ended December 31, 2012
		Nuclear decommissioning trust funds			Long-term investments			Interest rate options
		(dollars in thousands)
Assets:
Balance at December 31, 2011	$	(982	)	$	7,713		$	69,446
Total gains or losses (realized/unrealized):
Included in earnings (or changes in net assets)		982			887			(43,663	)
Purchases, issuances, liquidations		–			(8,600	)		–
Balance at December 31, 2012	$	–		$	–		$	25,783

		Year Ended December 31, 2011
		Nuclear decommissioning trust funds			Long-term investments			Interest rate options
		(dollars in thousands)
Assets:
Balance at December 31, 2010	$	(452	)	$	8,671		$	–
Total gains or losses (realized/unrealized):
Included in earnings (or changes in net assets)		(530	)		142			(30,554	)
Purchases, issuances, liquidations		–			(1,100	)		100,000
Balance at December 31, 2011	$	(982	)	$	7,713		$	69,446

Schedule of estimated fair values of long term debt, including current maturities

The estimated fair values of our long-term debt, including current maturities at December 31, 2012 and 2011 were as follows (in thousands):

		2012				2011
		Carrying Value		Fair Value		Carrying Value		Fair Value
Long-term debt	$	5,930,449	$	7,213,365	$	5,692,504	$	6,908,763