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Summary of Significant Accounting Policies - Other Expense (Income) - Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Interest income	$ 5	$ 6	$ 2
Interest on regulatory deferrals	9	9	2
Equity-related AFUDC	9	7	7
Non-service portion of pension and other postretirement benefit expenses	2		3
Earnings (losses) on investments	(7)	(3)	48
Other income	4		1
Total	$ 22	$ 19	$ 63

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Interest On Regulatory Deferrals

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Amount of realized and unrealized gain (loss) on investment.

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