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Summary of Significant Accounting Policies and Other Matters - Narrative (Details) $ / shares in Units, $ in Millions | 1 Months Ended | 3 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jan. 31, 2016 mi | Mar. 31, 2024 USD ($) project shares | Mar. 31, 2023 USD ($) dealer $ / shares shares | Dec. 31, 2019 USD ($) | Apr. 30, 2024 USD ($) | Dec. 31, 2023 | Mar. 01, 2023 project | Dec. 31, 2022
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Antidilutive shares (in shares) | shares |  | 0 | 1,900,000 |  |  |  |  |
Number of dealers | dealer |  |  | 2 |  |  |  |  |
Par value of common stock (in usd per share) | $ / shares |  |  | $ 0.10 |  |  |  |  |
Authorized repurchased amount |  |  | $ 1,000 |  |  |  |  |
Disposal Group, Held-for-sale, Not Discontinued Operations | Clean Energy Businesses |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Tax equity projects | project |  | 3 |  |  |  |  | 2 |
Mountain Valley Pipeline LLC | Con Edison Gas Pipeline and Storage, LLC |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Ownership percentage (in percent) |  | 7.20% |  |  |  | 7.90% |  | 9.60%
Number of miles in pipeline construction | mi | 300 |  |  |  |  |  |  |
Cash contributions for equity method investments |  | $ 530 |  | $ 530 |  |  |  |
Equity method investment, ownership percentage, expected percentage |  | 0.0675 |  |  |  |  |  |
Equity method investment, project percent completion (in percent) |  | 99.00% |  |  |  | 97.00% |  |
Equity method investments |  | $ 153 |  |  |  |  |  |
Mountain Valley Pipeline LLC | Con Edison Gas Pipeline and Storage, LLC | Subsequent Event |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Aggregate project cost |  |  |  |  | $ 7,850 |  |  |
Mountain Valley Pipeline LLC | Con Edison Gas Pipeline and Storage, LLC | Mountain Valley Pipeline LLC |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Ownership percentage (in percent) | 12.50% |  |  |  |  |  |  |
Broken Bow II | Clean Energy Businesses | Electric Energy (MWh) |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Deferred projects | project |  | 1 |  |  |  |  | 1 |

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