Operating Revenue (Schedule of Operating Revenue) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		$ 3,840	$ 3,827
Other revenues	[1],[2]	30	111
Total operating revenue		3,870	3,938
Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,155	1,158
Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		719	798
Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		178	182
Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		189	219
Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		43	33
Nonregulated Electric Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		249	232
Regulated Gas Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		630	548
Regulated Gas Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		206	191
Regulated Gas Sales | Other
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		34	28
Nonregulated Gas Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		52	83
Regulated Gas Transportation and Storage
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		271	232
Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3]	66	92
Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	48	31
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,807	1,909
Other revenues	[2],[4]	23	21
Total operating revenue		1,830	1,930
Virginia Electric and Power Company | Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		889	896
Virginia Electric and Power Company | Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		547	614
Virginia Electric and Power Company | Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		91	97
Virginia Electric and Power Company | Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		176	203
Virginia Electric and Power Company | Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		26	24
Virginia Electric and Power Company | Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		57	62
Virginia Electric and Power Company | Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	$ 21	$ 13

[1] Amounts above include revenue associated with services provided to discontinued operations of $1 million and $2 million for the three months ended March 31, 2021 and 2020, respectively.

[2] Amounts above include alternative revenue of $22 million and $36 million at Dominion Energy and $20 million and $17 million at Virginia Power for the three months ended March 31, 2021 and 2020, respectively.

[3] Amounts above include sales which are considered to be goods transferred at a point in time. Such amounts include $7 million for both the three months ended March 31, 2021 and 2020, primarily consisting of sales of commodities related to nonregulated extraction activities and other miscellaneous products. Additionally, amounts above include sales of renewable energy credits. Such amounts included $6 million and $4 million for the three months ended March 31, 2021 and $4 million and $3 million for the three months ended March 31, 2020, at Dominion Energy and Virginia Power, respectively.

[4] See Notes 10 and 19 for amounts attributable to related parties and affiliates.