Operating Segments - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
External revenue	$ 1,083	$ 863	$ 2,841	$ 2,299
Comprehensive income (loss) available (attributable) to common shareholder	168	144	390	64
Dominion Energy South Carolina, Inc. [Member]
Segment Reporting Information [Line Items]
External revenue	1,083	863	2,841	2,299
Comprehensive income (loss) available (attributable) to common shareholder	169	149	392	325
Corporate and Other
Segment Reporting Information [Line Items]
External revenue	0	0	0	0
Comprehensive income (loss) available (attributable) to common shareholder	$ (1)	$ (5)	$ (2)	$ (261)