Summary of Significant Accounting Policies and Other Matters - Investments (Details)	12 Months Ended
	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%