Operating Revenue (Schedule of Operating Revenue) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		$ 3,434	$ 3,536	$ 10,358	$ 10,350
Other revenues	[1],[2]	(258)	71	(274)	301
Total operating revenue		3,176	3,607	10,084	10,651
Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,281	1,497	3,453	3,746
Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		831	865	2,311	2,391
Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		194	190	547	548
Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		258	239	670	651
Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		52	37	131	99
Nonregulated Electric Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		253	218	719	627
Regulated Gas Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		132	123	950	853
Regulated Gas Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		61	50	346	304
Regulated Gas Sales | Other
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		31	18	88	61
Nonregulated Gas Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		7	12	74	124
Regulated Gas Transportation and Storage
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		208	165	698	578
Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		47	61	187	236
Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3]	79	61	184	132
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,987	2,231	5,517	5,905
Other revenues	[1],[4]	(11)	17	30	78
Total operating revenue		1,976	2,248	5,547	5,983
Virginia Electric and Power Company | Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		935	1,146	2,572	2,860
Virginia Electric and Power Company | Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		604	645	1,715	1,805
Virginia Electric and Power Company | Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		94	98	268	284
Virginia Electric and Power Company | Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		241	223	625	603
Virginia Electric and Power Company | Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		31	25	79	70
Virginia Electric and Power Company | Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		37	61	165	217
Virginia Electric and Power Company | Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	$ 45	$ 33	$ 93	$ 66

[1] Includes alternative revenue of $3 million and $51 million at Dominion Energy and $3 million and $12 million at Virginia Power for the three months ended September 30, 2021 and 2020, respectively, and $50 million and $90 million at Dominion Energy and $41 million and $63 million at Virginia Power for the nine months ended September 30, 2021 and 2020, respectively.

[2] Includes revenue associated with services provided to discontinued operations of $1 million and $1 million for the three months ended September 30, 2021 and 2020, respectively, and $3 million and $4 million for the nine months ended September 30, 2021 and 2020, respectively.

[3] Includes sales which are considered to be goods transferred at a point in time of $9 million and $5 million for the three months ended September 30, 2021 and 2020, respectively, and $24 million and $16 million for the nine months ended September 30, 2021 and 2020, respectively, at Dominion Energy, primarily consisting of sales of commodities related to nonregulated extraction activities and other miscellaneous products. Additionally, sales of renewable energy credits were $16 million and $21 million for the three months ended September 30, 2021 and 2020, respectively, and $29 million and $32 million for the nine months ended September 30, 2021 and 2020, respectively, at Dominion Energy and $13 million and $16 million for the three months ended September 30, 2021 and 2020, respectively, and $22 million and $24 million for the nine months ended September 30, 2021 and 2020, respectively, at Virginia Power.

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