Operating Revenue (Schedule of Operating Revenue) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		$ 3,084	$ 3,002	$ 6,924	$ 6,792
Other revenues	[1],[2]	(46)	104	(16)	252
Total operating revenue		3,038	3,106	6,908	7,044
Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,017	1,091	2,172	2,249
Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		761	728	1,480	1,526
Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		175	176	353	358
Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		223	193	412	412
Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		36	29	79	62
Nonregulated Electric Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		217	177	466	409
Regulated Gas Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		188	182	818	730
Regulated Gas Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		79	63	285	254
Regulated Gas Sales | Other
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		23	17	57	45
Nonregulated Gas Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		15	29	67	112
Regulated Gas Transportation and Storage
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		219	182	490	414
Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		74	96	140	151
Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3]	57	39	105	70
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,723	1,765	3,530	3,674
Other revenues	[1],[4]	18	40	41	61
Total operating revenue		1,741	1,805	3,571	3,735
Virginia Electric and Power Company | Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		748	818	1,637	1,714
Virginia Electric and Power Company | Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		564	546	1,111	1,160
Virginia Electric and Power Company | Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		83	89	174	186
Virginia Electric and Power Company | Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		208	177	384	380
Virginia Electric and Power Company | Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		22	21	48	45
Virginia Electric and Power Company | Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		71	94	128	156
Virginia Electric and Power Company | Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	$ 27	$ 20	$ 48	$ 33

[1] Includes alternative revenue of $25 million and $39 million at Dominion Energy and $18 million and $34 million at Virginia Power for the three months ended June 30, 2021 and 2020, respectively, and $47 million and $75 million at Dominion Energy and $38 million and $51 million at Virginia Power for the six months ended June 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 June 30, 2021 and 2020, respectively, and $2 million and $3 million for the six months ended June 30, 2021 and 2020, respectively.

[3] Includes sales which are considered to be goods transferred at a point in time of $8 million and $4 million for the three months ended June 30, 2021 and 2020, respectively, and $15 million and $11 million for the six months ended June 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 $7 million for both the three months ended June 30, 2021 and 2020, and $13 million and $11 million for the six months ended June 30, 2021 and 2020, respectively, at Dominion Energy and $5 million for both the three months ended June 30, 2021 and 2020, and $9 million and $8 million for the six months ended June 30, 2021 and 2020, respectively, at Virginia Power.

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