Operating Segments (Schedule of Segment Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
External revenue	$ 624	$ 698	$ 1,296	$ 363
Comprehensive income (loss) available (attributable) to common shareholder	69	(78)	157	(1,187)
Dominion Energy South Carolina | Operating Segment
Segment Reporting Information [Line Items]
External revenue	624	698	1,296	1,372
Comprehensive income (loss) available (attributable) to common shareholder	77	88	166	152
Corporate and Other | Operating Segment
Segment Reporting Information [Line Items]
External revenue	0	0	0	(1,009)
Comprehensive income (loss) available (attributable) to common shareholder	$ (8)	$ (166)	$ (9)	$ (1,339)