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Non-Derivative Fair Value Measurements (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Dec. 31, 2023
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Equity investments in unconsolidated subsidiaries |  | $ 251 |  |  | $ 244 |
Miscellaneous investments |  | 152 |  |  | 144 |
Debt Securities, Available-for-sale, Unrealized Gain |  | 1,300 |  | $ 1,200 |  |
Debt Securities, Available-for-sale, Unrealized Loss |  | 40 |  | 29 |  |
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |  |  |
Due in one year or less |  | 5 |  |  |  |
Due in 1 to 5 years |  | 289 |  |  |  |
Due in 5 to 10 years |  | 266 |  |  |  |
Due after 10 years |  | 255 |  |  |  |
Total |  | 815 |  |  |  |
Debt Securities, Available-for-sale, Unrealized Gain |  | 1,300 |  | 1,200 |  |
Debt Securities, Available-for-sale, Unrealized Loss |  | 40 |  | $ 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 |  | 2,107 | [1] |  | 2,054 | [2]
Fair Value Measured on a Recurring Basis | Cost | Cash equivalents |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Cash equivalents |  | 43 | [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] | 713 |  |  |  |
Fair Value Measured on a Recurring Basis | Cost | Debt securities |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Debt securities |  | 834 | [1] |  | 784 | [2]
Fair Value Measured on a Recurring Basis | Cost | Equity securities |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Equity Securities, FV-NI |  | 517 | [1] |  | 508 | [2]
Fair Value Measured on a Recurring Basis | Fair Value |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Alternative investment |  | 1,036 | [1] |  | 1,049 | [2]
Decommissioning Fund Investments |  | 3,388 | [1] |  | 3,211 | [2]
Fair Value Measured on a Recurring Basis | Fair Value | Cash equivalents |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Cash equivalents |  | 43 | [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 |  | 1,036 | [1] |  | 1,049 | [2]
Investments, Fair Value Disclosure |  | 1,036 |  |  |  |
Fair Value Measured on a Recurring Basis | Fair Value | Debt securities |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Debt securities |  | 815 | [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 |  | 1,494 | [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 |  | 1,536 | [1] |  | 1,380 | [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Cash equivalents |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Cash equivalents |  | 43 | [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 |  | 1,493 | [1] |  | 1,339 | [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Decommissioning Fund Investments |  | 802 | [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 |  | 801 | [1] |  | 771 | [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Equity securities |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Equity Securities, FV-NI |  | 1 | [1] |  | 2 | [2]
Fair Value Measured on a Recurring Basis | Fair Value | Level 3 |  |  |  |  |  |
Nuclear decommissinoning fund [Abstract] |  |  |  |  |  |
Decommissioning Fund Investments |  | 14 | [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 |  | 14 | [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 $251 million of equity method investments and $152 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.

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- Definition Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 107 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-107 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 35 -Paragraph 54B -Publisher FASB -URI https://asc.fasb.org/1943274/2147482134/820-10-35-54B Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A + Details
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477268/942-320-50-3A + Details
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477268/942-320-50-3A + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition 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. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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