Operating Revenue (Schedule of Operating Revenue) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		$ 4,081	$ 3,362	$ 11,457	$ 9,631
Other revenues	[1]	188	89	640	374
Operating revenue	[2]	4,269	3,451	12,097	10,005
Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,440	1,036	3,180	2,641
Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		962	737	2,347	1,897
Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		227	143	474	371
Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		244	224	658	647
Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		45	30	134	95
Nonregulated Electric Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		197	322	688	1,022
Regulated Gas Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		121	73	900	553
Regulated Gas Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		52	15	316	152
Regulated Gas Sales | Other
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		23	3	86	14
Nonregulated Gas Sales
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		51	42	369	139
Regulated Gas Transportation and Storage | FERC-regulated
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		248	266	772	800
Regulated Gas Transportation and Storage | State-regulated
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		168	138	547	472
Nonregulated gas transportation and storage
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		153	162	501	286
Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3]	54	38	180	132
Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	96	133	305	410
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		2,250	2,210	6,116	5,787
Other revenues	[1],[4]	14	22	51	22
Operating revenue	[5]	2,264	2,232	6,167	5,809
Virginia Electric and Power Company | Regulated Electric Sales | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,085	1,036	2,816	2,641
Virginia Electric and Power Company | Regulated Electric Sales | Commercial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		732	737	2,049	1,897
Virginia Electric and Power Company | Regulated Electric Sales | Industrial
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		121	143	351	371
Virginia Electric and Power Company | Regulated Electric Sales | Government and Other Retail
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		224	224	625	647
Virginia Electric and Power Company | Regulated Electric Sales | Wholesale
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		31	30	97	95
Virginia Electric and Power Company | Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3]	36	30	124	95
Virginia Electric and Power Company | Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[4]	21	10	54	41
Dominion Energy Gas Holdings, LLC
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		392	423	1,302	1,407
Other revenues				1	1
Operating revenue	[6]	392	423	1,303	1,408
Dominion Energy Gas Holdings, LLC | Regulated Gas Transportation and Storage | FERC-regulated
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[4]	180	179	566	561
Dominion Energy Gas Holdings, LLC | Regulated Gas Transportation and Storage | State-regulated
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[4]	139	131	460	450
Dominion Energy Gas Holdings, LLC | Regulated Gas Transportation and Storage | Residential
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		9	12	51	54
Dominion Energy Gas Holdings, LLC | Regulated Gas Transportation and Storage | Other
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1		3	9
Dominion Energy Gas Holdings, LLC | Nonregulated gas transportation and storage
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[4]	2	2	5	5
Dominion Energy Gas Holdings, LLC | Other Regulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[4]	4	4	17	16
Dominion Energy Gas Holdings, LLC | Other Nonregulated Revenues
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	3	3	7	9
Dominion Energy Gas Holdings, LLC | NGL Production
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[3],[4]	31	42	112	146
Dominion Energy Gas Holdings, LLC | Management Service
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	[4]	$ 23	$ 50	$ 81	$ 157

[1] Amounts above include alternative revenue of $9 million and $44 million at Dominion Energy and $9 million and $35 million at Virginia Power for the three and nine months ended September 30, 2019, respectively.

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

[3] Amounts above include $36 million and $28 million for the three months ended September 30, 2019, $108 million and $91 million for the three months ended September 30, 2018, $129 million and $101 million for the nine months ended September 30, 2019 and $170 million and $138 million for the nine months ended September 30, 2018 primarily consisting of NGL sales at Dominion Energy and Dominion Energy Gas, respectively, which are considered to be goods transferred at a point in time.

[4] See Notes 10 and 20 for amounts attributable to related parties and affiliates

[5] See Note 20 for amounts attributable to affiliates.

[6] See Note 20 for amounts attributable to related parties.