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Nuclear Decommissioning Fund (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Unrealized Gain $ 1,200 $ 1,000
Debt Securities, Available-for-Sale, Unrealized Loss 29 90
Equity investments in unconsolidated subsidiaries 244 219
Miscellaneous investments 144 133
Final Contractual Maturity [Abstract]    
Due in 1 Year or Less 4  
Due in 1 to 5 Years 261  
Due in 5 to 10 Years 269  
Due after 10 Years 246  
Total 780  
Fair Value Measured on a Recurring Basis | Cost    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Decommissioning fund investments 2,054 [1] 1,976 [2]
Fair Value Measured on a Recurring Basis | Cost | Cash equivalents    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents 41 [1] 29 [2]
Fair Value Measured on a Recurring Basis | Cost | Commingled Funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments, Fair Value Disclosure 721 [1] 803 [2]
Fair Value Measured on a Recurring Basis | Cost | Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 784 [1] 738 [2]
Fair Value Measured on a Recurring Basis | Cost | Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI, Current 508 [1] 406 [2]
Fair Value Measured on a Recurring Basis | Fair Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Alternative Investment 1,049 [1] 1,178 [2]
Decommissioning fund investments 3,211 2,882
Fair Value Measured on a Recurring Basis | Fair Value | Cash equivalents    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents 41 [1] 29 [2]
Alternative Investment 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Commingled Funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Alternative Investment 1,049 [1] 1,178 [2]
Investments, Fair Value Disclosure 1,049 [1] 1,178 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Alternative Investment 0 [1] 0 [2]
Debt Securities, Available-for-Sale, Excluding Accrued Interest 780 [1] 675 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Alternative Investment 0 [1] 0 [2]
Equity Securities, FV-NI, Current 1,341 [1] 1,000 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Decommissioning fund investments 1,380 [1] 1,028 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Cash equivalents    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents 41 [1] 29 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Commingled Funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments, Fair Value Disclosure 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI, Current 1,339 [1] 999 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Decommissioning fund investments 773 [1] 670 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Cash equivalents    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Commingled Funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments, Fair Value Disclosure 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 771 [1] 669 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI, Current 2 [1] 1 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Decommissioning fund investments 9 [1] 6 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Cash equivalents    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Commingled Funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments, Fair Value Disclosure 0 [1] 0 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 9 [1] 6 [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI, Current $ 0 [1] $ 0 [2]
[1] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $244 million of equity method investments and $144 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 $219 million of equity investments in unconsolidated subsidiaries and $133 million of rabbi trust assets and other miscellaneous investments.