Fair Value (Tables)

12 Months Ended

Dec. 31, 2024

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 Consolidated Balance Sheets as of December 31 (dollars in millions):

	2024				2023
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Long-term debt (Level 2)	$	1,100	$	938	$	1,100	$	969
Long-term debt (Level 3)		1,534		1,163		1,450		1,167
Snettisham finance lease obligation (Level 3)		39		35		42		40
Long-term debt to affiliated trusts (Level 3)		52		47		52		46

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 Consolidated Balance Sheets as of 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
December 31, 2024
Assets:
Energy commodity derivatives (2)	$	—	$	23	$	—	$	(13	)	$	10
Interest rate swap derivatives		—		1		—		—			1
Equity investments (3)		—		—		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

The following table discloses by level within the fair value hierarchy the Company’s assets and liabilities measured and reported on the Consolidated Balance Sheets as of December 31, 2023 at fair value on a recurring basis (dollars in millions):

	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
December 31, 2023
Assets:
Energy commodity derivatives (2)	$	—	$	31	$	—	$	(23	)	$	8
Interest rate swap derivatives		—		4		—		—			4
Equity investments (3)		—		—		50		—			50
Deferred compensation assets:
Mutual Funds:
Fixed income securities (3)		1		—		—		—			1
Equity securities (3)		7		—		—		—			7
Total	$	8	$	35	$	50	$	(23	)	$	70
Liabilities:
Energy commodity derivatives (2)	$	—	$	92	$	8	$	(65	)	$	35
Total	$	—	$	92	$	8	$	(65	)	$	35

(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 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 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 December 31, 2024 (dollars in millions, except mmBTU amounts):

	Fair Value (Net) at
	December 31, 2024			Valuation Technique	Unobservable Input	Range
Natural gas exchange	$	(3	)	Internally derived weighted average cost of gas	Forward sales prices	$2.28 - $4.57/mmBTU $3.18 Weighted Average
					Sales volumes	280,000 - 600,000 mmBTUs

	Fair Value at
	December 31, 2024		Valuation Technique	Unobservable Input	Range
Equity investments	$	53	Market approach	Comparable enterprise values	$130-$389 $246 Average
				Time to liquidity event	1.5 years
			Discounted cash flows	Revenue market multiples	0.49x to 6.02x Revenue 2.11x Average
				Market exit reduction	50%
				Discount rate	25%
				Annual revenues	$23-$153
				Terminal date	2029

Schedule of Activity For Energy Commodity Derivative Assets (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 years ended December 31 (dollars in millions):

	Natural Gas Exchange Agreement (1)			Equity Investments			Total
2024:
Balance as of January 1, 2024	$	(8	)	$	50		$	42
Total gains or (losses) (realized/unrealized):
Included in regulatory assets		5			—			5
Purchases and debt conversions		—			3			3
Ending balance as of December 31, 2024	$	(3	)	$	53		$	50
2023:
Balance as of January 1, 2023	$	(18	)	$	54		$	36
Total gains or (losses) (realized/unrealized):
Included in regulatory assets		10			—			10
Recognized in net income		—			(4	)		(4	)
Purchases and debt conversions		—			3			3
Other		—			(3	)		(3	)
Ending balance as of December 31, 2023	$	(8	)	$	50		$	42
2022:
Balance as of January 1, 2022	$	(8	)	$	—		$	(8	)
Transfers in (2)		—			21			21
Total gains (realized/unrealized):
Included in regulatory assets		(5	)		—			(5	)
Recognized in net income		—			33			33
Settlements		(5	)		—			(5	)
Ending balance as of December 31, 2022	$	(18	)	$	54		$	36

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

(2)The Company elected to account for certain equity investments at recurring fair value in 2022; as such, the transfer in represents the value as of the date of the election. See further discussion within Note 7.