Fair Value (Tables)

6 Months Ended

Jun. 30, 2013



				Fair Value Measurements at Reporting Date Using
		June 30, 2013			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)

		(dollars in thousands)
Nuclear decommissioning trust funds:
Domestic equity	$	134,766		$	134,766	$	—		$	—
International equity		47,471			47,471		—			—
Corporate bonds		37,981			—		37,981			—
US Treasury and government agency securities		49,787			49,787		—			—
Agency mortgage and asset backed securities		27,904			—		27,904			—
Municipal Bonds		655			—		655			—
Other		13,026			13,026		—			—
Long-term investments:
Corporate bonds		4,856			—		4,856			—
US Treasury and government agency securities		7,096			7,096		—			—
Agency mortgage and asset backed securities		3,226			—		3,226			—
International equity		8,287			8,287		—			—
Mutual funds		53,761			53,761		—			—
Other		408			408		—			—
Interest rate options		43,680			—		—			43,680	⁽¹⁾
Natural gas swaps		(3,114	)		—		(3,114	)		—



				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)

		(dollars in thousands)
Nuclear decommissioning trust funds:
Domestic equity	$	118,329		$	118,329	$	—		$	—
International equity		48,105			48,105		—			—
Corporate bonds		53,172			—		53,172			—
US Treasury and government agency securities		46,626			46,626		—			—
Agency mortgage and asset backed securities		21,273			—		21,273			—
Other		13,280			13,280		—			—
Long-term investments:
Corporate bonds		5,762			—		5,762			—
US Treasury and government agency securities		7,387			7,387		—			—
Agency mortgage and asset backed securities		2,526			—		2,526			—
Mutual funds		60,972			60,972		—			—
Other		375			375		—			—
Bond, reserve and construction funds		1			1		—			—
Interest rate options		25,783			—		—			25,783	⁽¹⁾
Natural gas swaps		(1,085	)		—		(1,085	)		—

⁽¹⁾: Interest rate options as reflected on the unaudited condensed Balance Sheet include the fair value of the interest rate options offset by $36,070,000 and $8,950,000 of collateral received from the counterparties at June 30, 2013 and December 31, 2012, respectively.



		Three Months Ended June 30, 2013

	Interest rate options
		(dollars in thousands)
Assets (Liabilities):
Balance at March 31, 2013	$	26,539
Total gains or losses (realized/unrealized):
Included in earnings (or changes in net assets)		17,141

Balance at June 30, 2013	$	43,680



		Three Months Ended June 30, 2012

		Interest rate options

		(dollars in thousands)
Assets (Liabilities):
Balance at March 31, 2012	$	66,860
Total gains or losses (realized/unrealized):
Included in earnings (or changes in net assets)		(27,645	)

Balance at June 30, 2012	$	39,215



		Six Months Ended June 30, 2013

		Interest rate options

		(dollars in thousands)
Assets (Liabilities):
Balance at December 31, 2012	$	25,783
Total gains or losses (realized/unrealized):
Included in earnings (or changes in net assets)		17,897

Balance at June 30, 2013	$	43,680



		Six Months Ended June 30, 2012

		Decommissioning funds			Long-term investments			Interest Rate Options

		(dollars in thousands)
Assets (Liabilities):
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			—			(30,231	)
Impairment included in other comprehensive margin (deficit)		—			887			—
Liquidations		—			(8,600	)		—

Balance at June 30, 2012	$	—		$	—		$	39,215

The estimated fair values of our long-term debt, including current maturities at June 30, 2013 and December 31, 2012 were as follows (in thousands):