Regulatory Matters - EEGH - Potential Loss Contingencies (Details) - Eastern Gas Transmission and Storage, Inc. [Member] - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018
2012 FERC Case, Disallowance Of Plant, Resolved In Q4 2018 [Member]
Regulatory Liabilities [Line Items]
Litigation Settlement, Expense		$ 129
Litigation Settlement, Expense, Net of Tax		$ 94
FERC Case, Disallowance Of Capitalized AFUDC, Resolved In December 2020 [Member]
Regulatory Liabilities [Line Items]
Litigation Settlement, Expense	$ 43
Litigation Settlement, Expense, Net of Tax	$ 31