Operating Segments - Schedule of Segment Information (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating Revenue	[1]	$ 1,929	$ 2,762	$ 3,070
Depreciation and amortization		450	327	312
Interest charges	[1]	260	303	288
Income tax expense (benefit)		(12)	(416)	(171)
Comprehensive income (loss) available (attributable) to common shareholder		(1,239)	(613)	(185)
Capital expenditures		497	633	928
Total assets		14,301	14,963
Operating Segment | Dominion Energy South Carolina
Segment Reporting Information [Line Items]
Operating Revenue		2,937	2,763	3,070
Depreciation and amortization		452	327	312
Interest charges		247	306	288
Income tax expense (benefit)		163	98	257
Comprehensive income (loss) available (attributable) to common shareholder		408	304	505
Capital expenditures		497	633	928
Total assets		14,300	15,000
Operating Segment | Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenue		(1,008)	(1)	0
Depreciation and amortization		(2)	0	0
Interest charges		13	(3)	0
Income tax expense (benefit)		(175)	(514)	(428)
Comprehensive income (loss) available (attributable) to common shareholder		(1,647)	(917)	(690)
Capital expenditures		0	0	$ 0
Total assets		$ 0	$ 0

[1] See Note 16 for amounts attributable to affiliates.