Fair Value (Tables)

6 Months Ended

Jun. 30, 2025

Fair Value Disclosures [Abstract]

Schedule of Carrying Value and Estimated Fair Value of Financial Instruments

The following table sets forth the carrying value and estimated fair value of the Company’s financial instruments not reported at estimated fair value on the Condensed Consolidated Balance Sheets as of June 30, 2025 and December 31, 2024 (dollars in millions):

	June 30, 2025				December 31, 2024
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Long-term debt (Level 2)	$	1,100	$	937	$	1,100	$	938
Long-term debt (Level 3)		1,534		1,191		1,534		1,163
Snettisham finance lease obligation (Level 3)		37		34		39		35
Long-term debt to affiliated trusts (Level 3)		52		47		52		47

Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis

The following table discloses by level within the fair value hierarchy the Company’s assets and liabilities measured and reported on the Condensed Consolidated Balance Sheets as of June 30, 2025 and December 31, 2024 at fair value on a recurring basis (dollars in millions):

	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
June 30, 2025
Assets:
Energy commodity derivatives	$	—	$	14	$	—	$	(12	)	$	2
Interest rate swap derivatives		—		1		—		—			1
Equity Investments		—		—		49		—			49
Deferred compensation assets
Mutual Funds:
Fixed income securities (3)		3		—		—		—			3
Equity securities (3)		6		—		—		—			6
Total	$	9	$	15	$	49	$	(12	)	$	61
Liabilities:
Energy commodity derivatives (2)	$	—	$	43	$	15	$	(25	)	$	33
Total	$	—	$	43	$	15	$	(25	)	$	33
December 31, 2024
Assets:
Energy commodity derivatives (2)	$	—	$	23	$	—	$	(13	)	$	10
Interest rate swap derivatives		—		1		—		—			1
Equity Investments		—		—		53		—			53
Deferred compensation assets
Mutual Funds:
Fixed income securities (3)		2		—		—		—			2
Equity securities (3)		7		—		—		—			7
Total	$	9	$	24	$	53	$	(13	)	$	73
Liabilities:
Energy commodity derivatives (2)	$	—	$	61	$	3	$	(37	)	$	27
Total	$	—	$	61	$	3	$	(37	)	$	27

(1)The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties.

(2)The Level 3 energy commodity derivative balances are associated with a natural gas exchange agreement.

(3)Included in other property and investments-net and other non-current assets on the Condensed Consolidated Balance Sheets.

Schedule of Quantitative Information

The following table presents the quantitative information which was used to estimate the fair values of the Level 3 assets and liabilities above as of June 30, 2025 (dollars in millions, except for per mmBTU amounts):

	Fair Value (Net) at			Valuation	Unobservable	Range and Weighted
	June 30, 2025			Technique	Input	Average Price
Natural gas exchange agreement	$	(15	)	Internally derived weighted average cost of gas	Forward purchase prices	$1.18 - $3.70/mmBTU $2.94 Weighted Average
					Forward sales prices	$2.63 - $8.60/mmBTU $6.52 Weighted Average
					Purchase volumes	270,000 - 469,009 mmBTUs
					Sales volumes	75,000 - 310,000 mmBTUs

The following table presents the quantitative information and assumptions which were used to estimate the fair values of the Level 3 equity investments as of June 30, 2025 (dollars in millions):

	Fair Value at
	June 30, 2025		Valuation Technique	Unobservable Input	Range
Equity investments	$	49	Market approach	Comparable enterprise values	$130-$389 $246 Average
				Time to liquidity event	1 year
			Discounted cash flows	Revenue market multiples	0.55x to 7.53x Revenue 2.33x Average
				Market multiple exit reduction	50%
				Discount rate	25%
				Annual revenues	$10 - $166
				Terminal date	2030

Schedule of Activity for Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)

The following table presents activity for assets and liabilities measured at fair value using significant unobservable inputs (Level 3) for the three and six months ended June 30 (dollars in millions):

	Natural Gas Exchange Agreement (1)			Equity Investments			Total
Three Months Ended June 30, 2025:
Beginning balance	$	(13	)	$	52		$	39
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities		(2	)		—			(2	)
Recognized in net income		—			(3	)		(3	)
Ending balance as of June 30, 2025	$	(15	)	$	49		$	34
Three Months Ended June 30, 2024:
Beginning balance	$	(7	)	$	52		$	45
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities		(1	)		—			(1	)
Recognized in net income		—			(2	)		(2	)
Ending balance as of June 30, 2024	$	(8	)	$	50		$	42
Six Months Ended June 30, 2025:
Beginning balance	$	(3	)	$	53		$	50
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities		(11	)		—			(11	)
Recognized in net income		—			(4	)		(4	)
Settlements		(1	)		—			(1	)
Ending balance as of June 30, 2025	$	(15	)	$	49		$	34
Six Months Ended June 30, 2024:
Beginning balance	$	(8	)	$	50		$	42
Total gains or (losses) (realized/unrealized):
Recognized in net income		—			(1	)		(1	)
Purchases and debt conversions		—			1			1
Ending balance as of June 30, 2024	$	(8	)	$	50		$	42

(1)There were no purchases, issuances or transfers from other categories during the periods presented in the table above.