Operating Segments (Schedule of Segment Reporting Information, by Segment) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Operating Revenue		$ 3,607	$ 3,782	$ 10,651	$ 10,506
Net income (loss) from discontinued operations including noncontrolling interest	[1],[2]	19	38	(1,753)	526
Net income (loss)		356	975	(1,083)	349
Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating Revenue	[3]	2,248	2,264	5,983	6,167
Net income (loss)		475	602	685	722
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		3,612	3,784	10,673	10,505
Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(5)	(2)	(22)	1
Adjustments & Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		9	12	36	62
Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(252)	(239)	(763)	(899)
Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		(243)	(227)	(727)	(837)
Dominion Energy Virginia
Segment Reporting Information [Line Items]
Operating Revenue		2,254	2,269	6,003	6,209
Net income (loss)		613	629	1,479	1,383
Dominion Energy Virginia | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating Revenue		2,248	2,264	5,983	6,196
Net income (loss)		615	628	1,477	1,379
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		2,257	2,275	6,013	6,219
Dominion Energy Virginia | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(3)	(6)	(10)	(10)
Gas Distribution
Segment Reporting Information [Line Items]
Operating Revenue		314	327	1,606	1,648
Net income (loss)		64	43	375	314
Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		311	321	1,597	1,635
Gas Distribution | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		3	6	9	13
Dominion Energy South Carolina
Segment Reporting Information [Line Items]
Operating Revenue		759	793	2,108	2,185
Net income (loss)		157	166	326	332
Dominion Energy South Carolina | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		758	792	2,105	2,182
Dominion Energy South Carolina | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		1	1	3	3
Contracted Assets
Segment Reporting Information [Line Items]
Operating Revenue		301	271	846	878
Net income (loss) from discontinued operations including noncontrolling interest		51	38	153	133
Net income (loss)		112	86	295	296
Contracted Assets | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		288	260	810	816
Contracted Assets | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		13	11	36	62
Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenue		222	349	815	423
Net income (loss) from discontinued operations including noncontrolling interest		(32)	0	(1,906)	393
Net income (loss)		(590)	51	(3,558)	(1,976)
Corporate and Other | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating Revenue		0	0	0	(29)
Net income (loss)		(140)	(26)	(792)	(657)
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		(11)	124	112	(409)
Corporate and Other | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		$ 233	$ 225	$ 703	$ 832

[1] Includes income tax expense (benefit) of $(10) million and $136 million for the three months ended September 30, 2020 and 2019, respectively and $(572) million and $47 million for the nine months ended September 30, 2020 and 2019, respectively.

[2] See Note 10 for amounts attributable to related parties.

[3] See Note 19 for amounts attributable to affiliates.