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Nuclear Decommissioning Trust Fund - Summary of Aggregate Fair Values and Realized Gains and Losses (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Nuclear decommissioning trust fund
Fair Value	$ 0	$ 838
Unrealized Gains		346
Unrealized Losses		36
Held-for-sale
Nuclear decommissioning trust fund
Fair Value	893
Unrealized Gains	390
Unrealized Losses	37
Cash and cash equivalents
Nuclear decommissioning trust fund
Fair Value		15
Unrealized Gains		0
Unrealized Losses		0
Cash and cash equivalents | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	25
Unrealized Gains	0
Unrealized Losses	$ 0
U.S. government and federal agency obligations
Nuclear decommissioning trust fund
Fair Value		86
Unrealized Gains		0
Unrealized Losses		$ 5
Weighted-average Maturities (In years)	12 years	11 years
U.S. government and federal agency obligations | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	$ 76
Unrealized Gains	0
Unrealized Losses	$ 9
Federal agency mortgage-backed securities
Nuclear decommissioning trust fund
Fair Value		$ 101
Unrealized Gains		0
Unrealized Losses		$ 11
Weighted-average Maturities (In years)	24 years	26 years
Federal agency mortgage-backed securities | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	$ 110
Unrealized Gains	0
Unrealized Losses	$ 13
Commercial mortgage-backed securities
Nuclear decommissioning trust fund
Fair Value		$ 35
Unrealized Gains		0
Unrealized Losses		$ 4
Weighted-average Maturities (In years)	29 years	30 years
Commercial mortgage-backed securities | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	$ 31
Unrealized Gains	0
Unrealized Losses	$ 4
Corporate debt securities
Nuclear decommissioning trust fund
Fair Value		$ 114
Unrealized Gains		0
Unrealized Losses		$ 13
Weighted-average Maturities (In years)	12 years	12 years
Corporate debt securities | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	$ 111
Unrealized Gains	0
Unrealized Losses	11
Equity securities
Nuclear decommissioning trust fund
Fair Value		$ 486
Unrealized Gains		346
Unrealized Losses		3
Equity securities | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	539
Unrealized Gains	390
Unrealized Losses	$ 0
Foreign government fixed income securities
Nuclear decommissioning trust fund
Fair Value		1
Unrealized Gains		0
Unrealized Losses		$ 0
Weighted-average Maturities (In years)	14 years	17 years
Foreign government fixed income securities | Held-for-sale
Nuclear decommissioning trust fund
Fair Value	$ 1
Unrealized Gains	0
Unrealized Losses	$ 0

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The weighted-average maturity period for securities of nuclear decommissioning trust funds assets.

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The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

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