Non-Derivative Fair Value Measurements (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2024		Jun. 30, 2023	Dec. 31, 2023
Nuclear decommissinoning fund [Abstract]
Equity investments in unconsolidated subsidiaries		$ 247			$ 244
Miscellaneous investments		151			144
Debt Securities, Available-for-sale, Unrealized Gain		1,300		$ 1,200
Debt Securities, Available-for-sale, Unrealized Loss		34		29
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Due in one year or less		6
Due in 1 to 5 years		276
Due in 5 to 10 years		257
Due after 10 years		251
Total		790
Debt Securities, Available-for-sale, Unrealized Gain		1,300		1,200
Debt Securities, Available-for-sale, Unrealized Loss		34		$ 29
Interest Rate Swap
Nuclear decommissinoning fund [Abstract]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net		1
Fair Value Measured on a Recurring Basis | Cost
Nuclear decommissinoning fund [Abstract]
Decommissioning Fund Investments		2,090	[1]		2,054	[2]
Fair Value Measured on a Recurring Basis | Cost | Cash equivalents
Nuclear decommissinoning fund [Abstract]
Cash equivalents		57	[1]		41	[2]
Fair Value Measured on a Recurring Basis | Cost | Commingled funds
Nuclear decommissinoning fund [Abstract]
Alternative investment	[2]				721
Investments, Fair Value Disclosure	[1]	718
Fair Value Measured on a Recurring Basis | Cost | Debt securities
Nuclear decommissinoning fund [Abstract]
Debt securities		804	[1]		784	[2]
Fair Value Measured on a Recurring Basis | Cost | Equity securities
Nuclear decommissinoning fund [Abstract]
Equity Securities, FV-NI		511	[1]		508	[2]
Fair Value Measured on a Recurring Basis | Fair Value
Nuclear decommissinoning fund [Abstract]
Alternative investment		1,042	[1]		1,049	[2]
Decommissioning Fund Investments		3,348	[1]		3,211	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Cash equivalents
Nuclear decommissinoning fund [Abstract]
Cash equivalents		57	[1]		41	[2]
Alternative investment		0	[1]		0	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Commingled funds
Nuclear decommissinoning fund [Abstract]
Alternative investment		1,042	[1]		1,049	[2]
Investments, Fair Value Disclosure		1,042
Fair Value Measured on a Recurring Basis | Fair Value | Debt securities
Nuclear decommissinoning fund [Abstract]
Debt securities		790	[1]		780	[2]
Alternative investment		0	[1]		0	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Equity securities
Nuclear decommissinoning fund [Abstract]
Equity Securities, FV-NI		1,459	[1]		1,341	[2]
Alternative investment		0	[1]		0	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1
Nuclear decommissinoning fund [Abstract]
Decommissioning Fund Investments		1,514	[1]		1,380	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Cash equivalents
Nuclear decommissinoning fund [Abstract]
Cash equivalents		57	[1]		41	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Commingled funds
Nuclear decommissinoning fund [Abstract]
Alternative investment	[2]				0
Investments, Fair Value Disclosure	[1]	0
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Debt securities
Nuclear decommissinoning fund [Abstract]
Debt securities		0	[1]		0	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Equity securities
Nuclear decommissinoning fund [Abstract]
Equity Securities, FV-NI		1,457	[1]		1,339	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2
Nuclear decommissinoning fund [Abstract]
Decommissioning Fund Investments		783	[1]		773	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Cash equivalents
Nuclear decommissinoning fund [Abstract]
Cash equivalents		0	[1]		0	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Commingled funds
Nuclear decommissinoning fund [Abstract]
Alternative investment	[2]				0
Investments, Fair Value Disclosure	[1]	0
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Debt securities
Nuclear decommissinoning fund [Abstract]
Debt securities		781	[1]		771	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Equity securities
Nuclear decommissinoning fund [Abstract]
Equity Securities, FV-NI		2	[1]		2	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3
Nuclear decommissinoning fund [Abstract]
Decommissioning Fund Investments		9	[1]		9	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Cash equivalents
Nuclear decommissinoning fund [Abstract]
Cash equivalents		0	[1]		0	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Commingled funds
Nuclear decommissinoning fund [Abstract]
Alternative investment	[2]				0
Investments, Fair Value Disclosure	[1]	0
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Debt securities
Nuclear decommissinoning fund [Abstract]
Debt securities		9	[1]		9	[2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Equity securities
Nuclear decommissinoning fund [Abstract]
Equity Securities, FV-NI		$ 0	[1]		$ 0	[2]

[1] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $247 million of equity method investments and $151 million of rabbi trust assets and other miscellaneous investments.

[2] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $244 million of equity investments in unconsolidated subsidiaries and $144 million of rabbi trust assets and other miscellaneous investments.