Acquisitions and Dispositions (Schedule of Capital Expenditures and Significant Noncash Items Reported As Discontinued Operations) (Detail) - USD ($) $ in Millions			12 Months Ended
		Nov. 06, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant noncash items
Charge related to a voluntary retirement program			$ 213	$ 119
Accrued capital expenditures	[1],[2],[3],[4],[5]		$ 555	307	$ 343
East Ohio
Business Acquisition [Line Items]
Capital expenditures		$ 299		352	348
Significant noncash items
Charge related to a voluntary retirement program		20		0		$ 0
Accrued capital expenditures		2		5	8
DGP
Business Acquisition [Line Items]
Capital expenditures		11		6	8
Significant noncash items
Impairment of assets and related charges		$ 0		$ (219)	$ 0

[1] See Note 2 for noncash investing and financing activities related to the adoption of a new accounting standard for leasing arrangements.

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

[3] See Note 5 for noncash activities related to the sale of a noncontrolling interest in Cove Point.

[4] See Note 9 for noncash investing activities related to the acquisition of a noncontrolling interest in Wrangler.

[5] See Notes 18,19 and 20 for noncash financing activities related to the acquisition of the public interest in Dominion Energy Midstream, the remarketing of RSNs, the issuance of stock purchase contracts associated with the 2019 Equity Units and the contribution of stock to Dominion Energy’s qualified defined benefit pension plan.