Operating Segments (Schedule of Segment Reporting Information, by Segment) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Operating revenue	[1]	$ 3,858	$ 3,466
Net income (loss)		(680)	503
Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating revenue	[2]	1,965	1,748
Net income (loss)		20	184
Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Operating revenue	[3]	511	526
Net income (loss)		116	166
Intersegment revenue
Segment Reporting Information [Line Items]
Operating revenue		(220)	(189)
Operating Segments
Segment Reporting Information [Line Items]
Operating revenue		3,858	3,466
Adjustments/Eliminations
Segment Reporting Information [Line Items]
Operating revenue			28
Net income (loss)		0	0
Eliminations
Segment Reporting Information [Line Items]
Operating revenue		(220)	(161)
Power Delivery
Segment Reporting Information [Line Items]
Operating revenue		598	563
Net income (loss)		155	156
Power Delivery | Intersegment revenue
Segment Reporting Information [Line Items]
Operating revenue		6	6
Power Delivery | Operating Segments
Segment Reporting Information [Line Items]
Operating revenue		604	569
Power Delivery | Operating Segments | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating revenue		598	563
Net income (loss)		154	154
Power Generation
Segment Reporting Information [Line Items]
Operating revenue		1,745	1,860
Net income (loss)		308	348
Power Generation | Intersegment revenue
Segment Reporting Information [Line Items]
Operating revenue		4	2
Power Generation | Operating Segments
Segment Reporting Information [Line Items]
Operating revenue		1,749	1,862
Power Generation | Operating Segments | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating revenue		1,396	1,400
Net income (loss)		204	222
Gas Infrastructure
Segment Reporting Information [Line Items]
Operating revenue		1,373	1,222
Net income (loss)		359	327
Gas Infrastructure | Intersegment revenue
Segment Reporting Information [Line Items]
Operating revenue		26	6
Gas Infrastructure | Operating Segments
Segment Reporting Information [Line Items]
Operating revenue		1,399	1,228
Gas Infrastructure | Operating Segments | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Operating revenue		511	526
Net income (loss)		119	167
Southeast Energy
Segment Reporting Information [Line Items]
Operating revenue		1,182
Net income (loss)		132
Southeast Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating revenue		1,182
Corporate and Other
Segment Reporting Information [Line Items]
Operating revenue		(1,040)	(207)
Net income (loss)		(1,634)	(328)
Corporate and Other | Intersegment revenue
Segment Reporting Information [Line Items]
Operating revenue		184	175
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Operating revenue		(856)	(32)
Corporate and Other | Operating Segments | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating revenue		(29)	(215)
Net income (loss)		(338)	(192)
Corporate and Other | Operating Segments | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Operating revenue		0	0
Net income (loss)		$ (3)	$ (1)

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

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

[3] See Note 19 for amounts attributable to related parties.