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Summary of Significant Accounting Policies and Other Matters - Investments (Details) | 12 Months Ended |  |  |  |  |  |  |
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Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2016 mi | Dec. 30, 2021 USD ($) | Jun. 30, 2021 USD ($) | May 31, 2021 | Mar. 31, 2021 USD ($) | Dec. 30, 2020 USD ($) | Dec. 31, 2019 USD ($) | Jan. 31, 2016
Stagecoach Gas Services, LLC |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Loss on sale of investment (pre-tax) |  | $ 212,000,000 |  |  |  |  |  |  |  |  |  |
Loss on sale of investment |  | 147,000,000 |  |  |  |  |  |  |  |  |  |
Equity method investments |  |  |  |  |  |  | $ 630,000,000 |  | $ 667,000,000 |  |  |
Mountain Valley Pipeline |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments | $ 530,000,000 | 530,000,000 |  |  |  |  |  |  |  |  |  |
Equity in earnings of subsidiaries | 33,000,000 |  |  |  |  |  |  |  |  |  |  |
CET | Mountain Valley Pipeline |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments | 144,000,000 | $ 111,000,000 |  |  |  |  |  |  |  |  |  |
CET | Stagecoach Gas Services, LLC | Subsidiaries |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale |  |  | $ 1,225,000,000 |  |  |  |  |  |  |  |  |
Equity method investment, ownership percent (in percent) |  | 50.00% |  |  |  |  |  | 50.00% |  |  |  |
Impairment loss | $ 414,000,000 |  |  |  |  |  |  |  |  |  |  |
CET Gas | Stagecoach Gas Services, LLC | Subsidiaries |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale |  |  | $ 629,000,000 |  |  |  |  |  |  |  |  |
CET Gas | Mountain Valley Pipeline |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership percent (in percent) | 7.90% | 9.60% | 10.20% | 11.30% |  |  |  |  |  |  |  |
Impairment loss | $ 0 | $ 0 | $ 231,000,000 | $ 320,000,000 |  |  |  |  |  |  |  |
Equity method investments |  |  |  |  |  |  |  |  |  |  | $ 530,000,000 |
Number of miles in pipeline construction | mi |  |  |  |  | 300 |  |  |  |  |  |  |
Expected reduction in equity interest | 7.00% |  |  |  |  |  |  |  |  |  |  |
Project, percent completion | 97.00% |  |  |  |  |  |  |  |  |  |  |
Long -term firm transportation contract period (in years) | 20 years |  |  |  |  |  |  |  |  |  |  |
Cash flows discount rate | 8.30% |  |  |  |  |  |  |  |  |  |  |
Impairment loss, after tax |  |  | 162,000,000 | 223,000,000 |  |  |  |  |  |  |  |
Carrying value of investment |  |  | 111,000,000 | 342,000,000 |  | $ 342,000,000 |  |  |  | $ 662,000,000 |  |
Deferred tax assets |  | $ 130,000,000 | 130,000,000 | $ 53,000,000 |  |  |  |  |  |  |  |
Increase in deferred tax assets |  |  | $ 77,000,000 |  |  |  |  |  |  |  |  |
CET Gas | Mountain Valley Pipeline | Mountain Valley Pipeline |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership percent (in percent) |  |  |  |  |  |  |  |  |  |  |  | 12.50%

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