Fair Value Measurements (Assets and Liabilities that are Measured at Fair Value on a Recurring Basis) (Detail) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		$ 1,444	$ 1,350
Total derivative liabilities		822	697
Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		279	298
Total derivative liabilities		289	316
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		8,611	7,865
Total Liabilities		822	697
Fair Value, Measurements, Recurring | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		4,122	3,770
Total Liabilities		289	316
Fair Value, Measurements, Recurring | Equity securities: | U.S.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	4,970	4,527
Fair Value, Measurements, Recurring | Equity securities: | U.S. | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	2,568	2,362
Fair Value, Measurements, Recurring | Fixed Income | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	552	500
Fair Value, Measurements, Recurring | Fixed Income | Corporate debt instruments | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	300	274
Fair Value, Measurements, Recurring | Fixed Income | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	1,418	1,457
Fair Value, Measurements, Recurring | Fixed Income | Government Securities | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	796	816
Fair Value, Measurements, Recurring | Fixed Income | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	222
Fair Value, Measurements, Recurring | Fixed Income | Other | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	176
Fair Value, Measurements, Recurring | Cash Equivalents and Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and other	[1]	5	31
Fair Value, Measurements, Recurring | Cash Equivalents and Other | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and other	[1]	3	20
Fair Value, Measurements, Recurring | Foreign Currency Exchange Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		3
Total derivative liabilities		108	39
Fair Value, Measurements, Recurring | Foreign Currency Exchange Rate | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		3
Total derivative liabilities		108	39
Fair Value, Measurements, Recurring | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		546	550
Total derivative liabilities		231	299
Fair Value, Measurements, Recurring | Commodity | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		104	117
Total derivative liabilities		160	232
Fair Value, Measurements, Recurring | Interest Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		895	800
Total derivative liabilities		483	359
Fair Value, Measurements, Recurring | Interest Rate | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		172	181
Total derivative liabilities		21	45
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		5,412	4,777
Fair Value, Measurements, Recurring | Level 1 | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		2,875	2,511
Fair Value, Measurements, Recurring | Level 1 | Equity securities: | U.S.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	4,970	4,527
Fair Value, Measurements, Recurring | Level 1 | Equity securities: | U.S. | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	2,568	2,362
Fair Value, Measurements, Recurring | Level 1 | Fixed Income | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	218	219
Fair Value, Measurements, Recurring | Level 1 | Fixed Income | Government Securities | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	129	129
Fair Value, Measurements, Recurring | Level 1 | Fixed Income | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	222
Fair Value, Measurements, Recurring | Level 1 | Fixed Income | Other | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	176
Fair Value, Measurements, Recurring | Level 1 | Cash Equivalents and Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and other	[1]	2	31
Fair Value, Measurements, Recurring | Level 1 | Cash Equivalents and Other | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and other	[1]	2	20
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		2,934	2,863
Total Liabilities		747	558
Fair Value, Measurements, Recurring | Level 2 | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		1,217	1,238
Total Liabilities		221	179
Fair Value, Measurements, Recurring | Level 2 | Fixed Income | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	552	500
Fair Value, Measurements, Recurring | Level 2 | Fixed Income | Corporate debt instruments | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	300	274
Fair Value, Measurements, Recurring | Level 2 | Fixed Income | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	1,200	1,238
Fair Value, Measurements, Recurring | Level 2 | Fixed Income | Government Securities | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	667	687
Fair Value, Measurements, Recurring | Level 2 | Cash Equivalents and Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and other	[1]	3
Fair Value, Measurements, Recurring | Level 2 | Cash Equivalents and Other | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and other	[1]	1
Fair Value, Measurements, Recurring | Level 2 | Foreign Currency Exchange Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		3
Total derivative liabilities		108	39
Fair Value, Measurements, Recurring | Level 2 | Foreign Currency Exchange Rate | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		3
Total derivative liabilities		108	39
Fair Value, Measurements, Recurring | Level 2 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		281	325
Total derivative liabilities		156	160
Fair Value, Measurements, Recurring | Level 2 | Commodity | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		74	96
Total derivative liabilities		92	95
Fair Value, Measurements, Recurring | Level 2 | Interest Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		895	800
Total derivative liabilities		483	359
Fair Value, Measurements, Recurring | Level 2 | Interest Rate | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		172	181
Total derivative liabilities		21	45
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		265	225
Total Liabilities		75	139
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		30	21
Total Liabilities		68	137
Fair Value, Measurements, Recurring | Level 3 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		265	225
Total derivative liabilities		75	139
Fair Value, Measurements, Recurring | Level 3 | Commodity | Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets		30	21
Total derivative liabilities		$ 68	$ 137

[1] Includes investments held in the nuclear decommissioning trusts and rabbi trusts. Excludes $294 million and $457 million of assets at Dominion Energy, inclusive of $94 million and $217 million at Virginia Power, at March 31, 2024 and December 31, 2023, respectively, measured at fair value using NAV (or its equivalent) as a practical expedient which are not required to be categorized in the fair value hierarchy.