Significant Accounting Policies (Schedule of Supplemental Cash Flow Information) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Supplemental Cash Flow Information [Line Items]
Interest and related charges, excluding capitalized amounts		$ 1,340	$ 1,519	$ 1,643
Income taxes		160	292	106
Significant noncash investing and financing activities:
Accrued capital expenditures	[1],[2],[3],[4],[5]	637	485	555
Leases	[1],[2],[3],[4],[5],[6]	96	173	157
Virginia Electric and Power Company
Schedule Of Supplemental Cash Flow Information [Line Items]
Interest and related charges, excluding capitalized amounts		501	491	495
Income taxes		109	452	272
Significant noncash investing and financing activities:
Accrued capital expenditures	[5],[7]	363	262	292
Leases	[5],[7],[8]	$ 79	$ 32	$ 55

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

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

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

[4] 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, the contribution of stock to Dominion Energy’s qualified defined benefit pension plan, derivative restructuring and the issuance of common stock associated with the settlement of litigation. See Note 23 for non-cash investing activities related to property, plant and equipment conveyed to satisfy litigation.

[5] See the New Accounting Standards section below for noncash investing and financing activities related to the adoption of a new accounting standard for leasing arrangements.

[6] Includes $47 million of finance leases and $49 million of operating leases entered in 2021, $46 million of finance leases and $127 million of operating leases entered in 2020 and $113 million of finance leases and $44 million of operating leases entered in 2019.

[7] See Note 18 for non-cash financing activities related to derivative restructuring.

[8] Includes $37 million of finance leases and $42 million of operating leases entered in 2021, $32 million of finance leases entered in, 2020 and $20 million of finance leases and $35 million of operating leases entered in 2019.