Operating Segments - Schedule of Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
External revenue	[1]	$ 704	$ 909	$ 1,463	$ 1,758
Comprehensive income (loss) available (attributable) to common shareholder		76	119	168	222
Dominion Energy South Carolina, Inc. [Member]
Segment Reporting Information [Line Items]
External revenue		704	909	1,463	1,758
Comprehensive income (loss) available (attributable) to common shareholder		63	119	149	223
Corporate and Other
Segment Reporting Information [Line Items]
External revenue		0	0	0	0
Comprehensive income (loss) available (attributable) to common shareholder		$ 13	$ 0	$ 19	$ (1)

[1] See Note 12 for amounts attributable to affiliates.