Regulatory Matters - EGTS (Details) - EGTS - USD ($) $ in Millions	1 Months Ended		3 Months Ended		5 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022
Schedule Of Regulatory Assets and Liabilities [Line Items]
Provision for rate refunds					$ 56
FERC Case, Disallowance Of Capitalized AFUDC, Resolved In December 2020
Schedule Of Regulatory Assets and Liabilities [Line Items]
Litigation settlement expense		$ 43
Litigation settlement expense, net of tax		$ 31
Litigation settlement, reduction in expense			$ 11	$ 11
Litigation settlement, reduction in expense, net of tax			$ 8	$ 8
General Rate Case | Federal Energy Regulatory Commission
Schedule Of Regulatory Assets and Liabilities [Line Items]
Proposed annual cost-of-service	$ 1,100
General Rate Case | Federal Energy Regulatory Commission | Gas Storage
Schedule Of Regulatory Assets and Liabilities [Line Items]
Proposed annual cost-of-service, rate increase	85.00%
General Rate Case | Federal Energy Regulatory Commission | Gas Transportation
Schedule Of Regulatory Assets and Liabilities [Line Items]
Proposed annual cost-of-service, rate increase	60.00%
General Rate Case, Depreciation Expense | Federal Energy Regulatory Commission
Schedule Of Regulatory Assets and Liabilities [Line Items]
Approved rate increase (decrease) amount					(30)
General Rate Case, Transportation and Storage Revenues | Federal Energy Regulatory Commission
Schedule Of Regulatory Assets and Liabilities [Line Items]
Approved rate increase (decrease) amount					$ 160