Equity (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2023
Class Of Stock [Line Items]
Common stock, par value	$ 0		$ 0
Common stock, shares authorized	50,000,000		50,000,000
Common stock, shares issued	40,300,000		40,300,000
Common stock, shares outstanding	40,300,000		40,300,000
Preferred stock, par value	$ 0		$ 0
Preferred stock, shares authorized	20,000,000		20,000,000
Preferred stock, shares issued	1,000		1,000
Preferred stock, shares outstanding	1,000		1,000
Dominion Energy
Class Of Stock [Line Items]
Contributions from SCANA		$ 150
Dominion Energy | FILOT
Class Of Stock [Line Items]
Common stock issued to satisfy the settlement		104
Dominion Energy | SCDOR | Common Stock
Class Of Stock [Line Items]
Common stock issued to satisfy the settlement	$ 72	$ 45