Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair value of assets and liabilities that are measured at fair value on a recurring basis

The following table presents the fair value at December 31, 2021, of our assets and liabilities that are measured at fair value on a recurring basis (dollars in thousands):

	Level 1		Level 2		Level 3		Other			Total
Assets
Risk management activities — derivative instruments:
Commodity contracts	$	—	$	115,079	$	—	$	(4,690)	(a)	$	110,389
Nuclear decommissioning trust:
Equity securities	45,264		—		—		(27,782)		(b)	17,482
U.S. commingled equity funds	—		—		—		595,048		(c)	595,048
U.S. Treasury debt	240,745		—		—		—			240,745
Corporate debt	—		203,454		—		—			203,454
Mortgage-backed securities	—		155,574		—		—			155,574
Municipal bonds	—		72,189		—		—			72,189
Other fixed income	—		10,265		—		—			10,265
Subtotal nuclear decommissioning trust	286,009		441,482		—		567,266			1,294,757
Other special use funds:
Equity securities	47,570		—		—		936		(b)	48,506
U.S. Treasury debt	298,170		—		—		—			298,170
Municipal bonds	—		11,734		—		—			11,734
Subtotal other special use funds	345,740		11,734		—		936			358,410
Total assets	$	631,749	$	568,295	$	—	$	563,512		$	1,763,556
Liabilities
Risk management activities — derivative instruments:
Commodity contracts	$	—	$	(4,740)	$	(2,738)	$	3,105	(a)	$	(4,373)

(a)Represents counterparty netting, margin, and collateral. See Note 16.

(b)Represents net pending securities sales and purchases.

(c)Valued using NAV as a practical expedient and, therefore, are not classified in the fair value hierarchy.

 The following table presents the fair value at December 31, 2020, of our assets and liabilities that are measured at fair value on a recurring basis (dollars in thousands):

	Level 1		Level 2		Level 3		Other			Total
Assets
Risk management activities — derivative instruments:
Commodity contracts	$	—	$	9,016	$	4	$	(4,271)	(a)	$	4,749
Nuclear decommissioning trust:
Equity securities	29,796		—		—		(17,828)		(b)	11,968
U.S. commingled equity funds	—		—		—		610,055		(c)	610,055
U.S. Treasury debt	164,514		—		—		—			164,514
Corporate debt	—		149,509		—		—			149,509
Mortgage-backed securities	—		99,623		—		—			99,623
Municipal bonds	—		89,705		—		—			89,705
Other fixed income	—		13,061		—		—			13,061
Subtotal nuclear decommissioning trust	194,310		351,898		—		592,227			1,138,435
Other special use funds:
Equity securities	37,337		—		—		504		(b)	37,841
U.S. Treasury debt	203,220		—		—		—			203,220
Municipal bonds	—		13,448		—		—			13,448
Subtotal other special use funds	240,557		13,448		—		504			254,509
Total assets	$	434,867	$	374,362	$	4	$	588,460		$	1,397,693
Liabilities
Risk management activities — derivative instruments:
Commodity contracts	$	—	$	(20,498)	$	(1,107)	$	2,986	(a)	$	(18,619)

(a)Represents counterparty netting, margin, and collateral. See Note 16.

(b)Represents net pending securities sales and purchases.

(c)Valued using NAV as a practical expedient and, therefore, are not classified in the fair value hierarchy.