Equity (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended
	May 31, 2022	Jun. 30, 2023	Dec. 31, 2022
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
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 | SCDOR | Common Stock
Class Of Stock [Line Items]
Common stock issued to satisfy the settlement	$ 72