Acquisitions and Dispositions (Schedule of Capital Expenditures and Significant Noncash Items Reported As Discontinued Operations) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Significant noncash items
Charges related to a voluntary retirement program				$ 0	$ 384
Depreciation, depletion and amortization		$ 595	$ 586	1,751	1,713
Accrued capital expenditures	[1],[2]			461	378
Dominion Energy Gas Holdings, LLC | Gas, Transmission & Storage
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Capital expenditures				240	265
Significant noncash items
Impairment of assets and other charges				463	13
Charges related to a voluntary retirement program				0	22
Depreciation, depletion and amortization				173	240
Accrued capital expenditures				43	42
Dominion Energy Gas Holdings, LLC | Q-Pipe Transaction
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Capital expenditures				27	32
Significant noncash items
Impairment of assets and other charges				0	0
Charges related to a voluntary retirement program				0	4
Depreciation, depletion and amortization				25	38
Accrued capital expenditures				$ 2	$ 3

[1] See Note 16 for noncash financing activities related to derivative restructuring, the acquisition of the public interest in Dominion Energy Midstream, the issuance of stock purchase contracts associated with the 2019 Equity Units and the issuance of common stock associated with the settlement of litigation.  See Note 17 for noncash investing activities related to property, plant and equipment conveyed to satisfy litigation. See Note 18 to the Consolidated Financial Statements in Dominion Energy’s Annual Report on Form 10-K for the year ended December 31, 2019 for noncash financing activities related to the remarketing of RSNs.

[2] See Note 3 for noncash investing and financing activities related to the SCANA Combination.