Fair Value (Tables)

9 Months Ended

Sep. 30, 2017

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


	Fair Value Measurements at Reporting Date Using
		September 30, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)

		(dollars in thousands)
Nuclear decommissioning trust funds:
Domestic equity	$	138,008	$	138,008	$	—
International equity trust		81,260		—		81,260
Corporate bonds		68,909		—		68,909
US Treasury and government agency securities		51,144		51,144		—
Agency mortgage and asset backed securities		35,153		—		35,153
Mutual funds		47,604		47,604		—
Municipal bonds		301		—		301
Other		5,407		5,407		—
Long-term investments:
International equity trust		20,712		—		20,712
Corporate bonds		15,173		—		15,173
US Treasury and government agency securities		11,608		11,608		—
Agency mortgage and asset backed securities		1,348		—		1,348
Mutual funds		75,479		75,479		—
Other		1,198		1,199		—
Natural gas swaps		807		—		807


	Fair Value Measurements at Reporting Date Using
		December 31, 2016			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)

		(dollars in thousands)
Nuclear decommissioning trust funds:
Domestic equity	$	170,408		$	170,408	$	—
International equity trust		66,861			—		66,861
Corporate bonds		60,019			—		60,019
US Treasury and government agency securities		65,725			65,725		—
Agency mortgage and asset backed securities		17,410			—		17,410
Municipal bonds		943			—		943
Other		4,663			4,663		—
Long-term investments:
Corporate bonds		11,853			—		11,853
US Treasury and government agency securities		12,187			12,187		—
Agency mortgage and asset backed securities		1,651			—		1,651
International equity trust		15,946			—		15,946
Mutual funds		57,932			57,932		—
Other		305			305		—
Natural gas swaps		(15,090	)		—		(15,090	)

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 September 30, 2017 and December 31, 2016 were as follows (in thousands):


		2017				2016

		Carrying Value		Fair Value		Carrying Value		Fair Value

Long-term debt	$	8,237,972	$	9,119,700	$	8,304,523	$	9,043,029