Accumulated Other Comprehensive Income (Loss) (Schedule of Changes in AOCI Net of Tax and Reclassifications out of AOCI by Component) (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended		9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022		Jun. 30, 2022		Sep. 30, 2023		Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]							$ 27,881
Income tax expense (benefit)		$ (182)		$ (70)				(432)		$ (61)
Net Income From Continuing Operations		717		626				1,864		261
Total other comprehensive income (loss)		1		22				7		84
Ending balance		28,028						28,028
Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		17,930		16,418		$ 15,980		17,245	[2]	15,980
Income before income tax expense		602		637				1,475		1,102
Income tax expense (benefit)		(129)		(66)				(317)		(127)
Total other comprehensive income (loss)		15		9				15		43
Ending balance		18,418		16,998		16,418		18,418		16,998
Total Derivative-Hedging Activities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(236)	[3],[4]	(283)	[3],[4]	(358)	[5],[6]	(249)	[5],[6]	(358)	[5],[6]
Other comprehensive income (loss) before reclassifications: gains (losses)		19	[3],[4]	10	[3],[4]			16	[5],[6]	64	[5],[6]
Income tax expense (benefit)		(3)	[3],[4]					(8)	[5],[6]
Total, net of tax		8	[3],[4]					24	[5],[6]
Total other comprehensive income (loss)		27	[3],[4]	22	[3],[4]			40	[5],[6]	97	[5],[6]
Ending balance	[3],[4]	(209)	[6]	(261)	[6]	(283)		(209)	[6]	(261)	[6]
Total Derivative-Hedging Activities | Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		13	[7],[8]	0	[7],[8]	(45)	[9],[10]	16	[9],[10]	(45)	[9],[10]
Other comprehensive income (loss) before reclassifications: gains (losses)		18	[7],[8]	13	[7],[8]			15	[9],[10]	57	[9],[10]
Income tax expense (benefit)		(1)	[7],[8]	(1)	[7],[8]			(1)	[9],[10]	(1)	[9],[10]
Total, net of tax		0	[7],[8]	0	[7],[8]			0	[9],[10]	1	[9],[10]
Total other comprehensive income (loss)		18	[7],[8]	13	[7],[8]			15	[9],[10]	58	[9],[10]
Ending balance	[7],[8]	31	[10]	13	[10]	0		31	[10]	13	[10]
Total Derivative-Hedging Activities | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		11	[3],[4]	16	[3],[4]			32	[3],[4]	44	[5],[6]
Discontinued operations	[3],[4]	0						0
Other income (expense)		0	[3],[4]	0	[3],[4]			0	[5],[6]	0	[5],[6]
Income (loss) before income tax expense		11	[3],[4]	16	[3],[4]			32	[5],[6]	44	[5],[6]
Income tax expense (benefit)				(4)	[3],[4]					(11)	[5],[6]
Total, net of tax				12	[3],[4]					33	[5],[6]
Total Derivative-Hedging Activities | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		1	[7],[8]	1	[7],[8]			1	[9],[10]	2	[9],[10]
Other income (expense)		0	[7],[8]	0	[7],[8]			0	[9],[10]	0	[9],[10]
Income (loss) before income tax expense		1	[7],[8]	1	[7],[8]			1	[9],[10]	2	[9],[10]
Investment Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(29)	[11]	(40)	[11]	37	[12]	(44)	[12]	37	[12]
Other comprehensive income (loss) before reclassifications: gains (losses)		(22)	[11]	(27)	[11]			(6)	[12]	(116)	[12]
Income tax expense (benefit)		0	[11]					0	[12]
Total, net of tax		2	[11]					1	[12]
Total other comprehensive income (loss)		(20)	[11]	(26)	[11]			(5)	[12]	(103)	[12]
Ending balance	[11]	(49)	[12]	(66)	[12]	(40)		(49)	[12]	(66)	[12]
Investment Securities | Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(4)	[13]	(7)	[13]	4	[14]	(7)	[14]	4	[14]
Other comprehensive income (loss) before reclassifications: gains (losses)		(3)	[13]	(4)	[13]			0	[14]	(14)	[14]
Income tax expense (benefit)		0	[13]	0	[13]			0	[14]	0	[14]
Total, net of tax		0	[13]	0	[13]			0	[14]	(1)	[14]
Total other comprehensive income (loss)		(3)	[13]	(4)	[13]			0	[14]	(15)	[14]
Ending balance	[13]	(7)	[14]	(11)	[14]	(7)		(7)	[14]	(11)	[14]
Investment Securities | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		0	[11]	0	[11]			0	[12]	0	[12]
Discontinued operations		0	[11]					0	[12]
Other income (expense)		2	[11]	2	[11]			1	[12]	18	[12]
Income (loss) before income tax expense		2	[11]	2	[11]			1	[12]	18	[12]
Income tax expense (benefit)				(1)	[11]					(5)	[12]
Total, net of tax				1	[11]					13	[12]
Investment Securities | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		0	[13]	0	[13]			0	[14]	0	[14]
Other income (expense)		0	[13]	0	[13]			0	[14]	(1)	[14]
Income (loss) before income tax expense		0	[13]	0	[13]			0	[14]	(1)	[14]
Pension and Other Postretirement Benefit Costs
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(1,299)	[15]	(1,070)	[15]	(1,133)	[16]	(1,276)	[16]	(1,133)	[16]
Other comprehensive income (loss) before reclassifications: gains (losses)		0	[15]	0	[15]			0	[16]	30	[16]
Income tax expense (benefit)		7	[15]					15	[16]
Total, net of tax		(8)	[15]					(31)	[16]
Total other comprehensive income (loss)		(8)	[15]	26	[15]			(31)	[16]	89	[16]
Ending balance	[15]	(1,307)	[16]	(1,044)	[16]	(1,070)		(1,307)	[16]	(1,044)	[16]
Pension and Other Postretirement Benefit Costs | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		0	[15]	0	[15]			0	[16]	0	[16]
Discontinued operations		0	[15]					0	[16]
Other income (expense)		(15)	[15]	35	[15]			(46)	[16]	80	[16]
Income (loss) before income tax expense		(15)	[15]	35	[15]			(46)	[16]	80	[16]
Income tax expense (benefit)				(9)	[15]					(21)	[16]
Total, net of tax				26	[15]					59	[16]
Equity Method Investees
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(2)	[17]	(3)	[17]	(4)	[18]	(3)	[18]	(4)	[18]
Other comprehensive income (loss) before reclassifications: gains (losses)		(1)	[17]	0	[17]			0	[18]	1	[18]
Income tax expense (benefit)		(1)	[17]					(1)	[18]	0	[18]
Total, net of tax		3	[17]					3	[18]	0	[18]
Total other comprehensive income (loss)		2	[17]	0	[17]			3	[18]	1	[18]
Ending balance	[17]	(0)	[18]	(3)	[18]	(3)		(0)	[18]	(3)	[18]
Equity Method Investees | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		0	[17]	0	[17]			0	[18]	0	[18]
Discontinued operations		4	[17]					4	[18]
Other income (expense)		0	[17]	0	[17]			0	[18]	0	[18]
Income (loss) before income tax expense		4	[17]	0	[17]			4	[18]	0	[18]
Income tax expense (benefit)	[17]			0
Total, net of tax	[17]			0
AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(1,566)		(1,396)		(1,458)		(1,572)		(1,458)
Other comprehensive income (loss) before reclassifications: gains (losses)		(4)		(17)				10		(21)
Income tax expense (benefit)		3						6
Total, net of tax		5						(3)
Total other comprehensive income (loss)		1		22				7		84
Ending balance		(1,565)		(1,374)		(1,396)		(1,565)		(1,374)
AOCI | Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		9		(7)		(41)		9		(41)
Other comprehensive income (loss) before reclassifications: gains (losses)		15		9				15		43
Income tax expense (benefit)		(1)		(1)				(1)		(1)
Total, net of tax		0		0				0		0
Total other comprehensive income (loss)		15		9				15		43
Ending balance		24		2		$ (7)		24		2
AOCI | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		11		16				32		44
Discontinued operations		(4)						4
Other income (expense)		(13)		37				(45)		98
Income (loss) before income tax expense		2		53				(9)		142
Income tax expense (benefit)				(14)						(37)
Total, net of tax				39						105
AOCI | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges (benefit)		1		1				1		2
Other income (expense)		0		0				0		(1)
Income (loss) before income tax expense		$ 1		$ 1				$ 1		$ 1

[1] Dominion Energy’s Consolidated Balance Sheet at December 31, 2022 has been derived from the audited Consolidated Balance Sheet at that date and recast for certain events as discussed in Note 1.

[2] Virginia Power’s Consolidated Balance Sheet at December 31, 2022 has been derived from the audited Consolidated Balance Sheet at that date.

[3] Comprised entirely of interest rate derivative hedging activities.

[4] Net of $70 million, $79 million, $87 million and $94 million tax at September 30, 2023, June 30, 2023, September 30, 2022 and June 30, 2022, respectively.

[5] Comprised entirely of interest rate derivative hedging activities.

[6] Net of $70 million, $83 million, $87 million and $119 million tax at September 30, 2023, December 31, 2022, September 30, 2022 and December 31, 2021, respectively.

[7] Comprised entirely of interest rate derivative hedging activities.

[8] Net of $(11) million, $(4) million, $(4) million and $— million tax at September 30, 2023, June 30, 2023, September 30, 2022 and June 30, 2022, respectively.

[9] Comprised entirely of interest rate derivative hedging activities.

[10] Net of $(11) million, $(5) million, $(4) million and $16 million tax at September 30, 2023, December 31, 2022, September 30, 2022 and December 31, 2021, respectively.

[11] Net of $16 million, $9 million, $23 million and $14 million tax at September 30, 2023, June 30, 2023, September 30, 2022 and June 30, 2022, respectively.

[12] Net of $16 million, $13 million, $23 million and $(10) million tax at September 30, 2023, December 31, 2022, September 30, 2022 and December 31, 2021, respectively.

[13] Net of $3 million, $1 million, $4 million and $3 million tax at September 30, 2023, June 30, 2023, September 30, 2022 and June 30, 2022, respectively.

[14] Net of $3 million, $2 million, $4 million and $(2) million tax at September 30, 2023, December 31, 2022, September 30, 2022 and December 31, 2021, respectively.

[15] Net of $461 million, $453 million, $367 million and $376 million tax at September 30, 2023, June 30, 2023, September 30, 2022 and June 30, 2022, respectively.

[16] Net of $461 million, $445 million, $367 million and $396 million tax at September 30, 2023, December 31, 2022, September 30, 2022 and December 31, 2021, respectively.

[17] Net of $— million, $— million, $1 million and $1 million tax at September 30, 2023, June 30, 2023, September 30, 2022 and June 30, 2022, respectively.

[18] Net of $— million, $1 million, $1 million and $1 million tax at September 30, 2023, December 31, 2022, September 30, 2022 and December 31, 2021, respectively.