Regulatory Matters (Narrative) (Detail) $ in Millions	1 Months Ended											2 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($)	Jul. 31, 2024 USD ($)	Jun. 30, 2024 USD ($) Bcf / d	May 31, 2024 USD ($)	Mar. 31, 2024 USD ($) mi kV	Feb. 29, 2024 USD ($)	Jan. 31, 2024 USD ($)	Nov. 30, 2023 USD ($)	Oct. 31, 2023 USD ($) Project MW	Jul. 31, 2023 USD ($)	May 31, 2023 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Virginia Regulation
Public Utilities General Disclosures [Line Items]
Percentage of earned return										9.04%
Authorized return percentage						9.35%				9.35%
Virginia Regulation | Annual Fuel Factor | Securitization Option
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement					$ 541
North Carolina Regulation
Public Utilities General Disclosures [Line Items]
Application date					2024-03
North Carolina Regulation | Rider DSM
Public Utilities General Disclosures [Line Items]
Increase (Decrease) in customer usage tracker					$ 31
North Carolina Regulation | Virginia Power Base Rate Case
Public Utilities General Disclosures [Line Items]
Increase(Decrease) in gas cost					$ 57
Percentage of earned return					5.01%
Percentage of proposed earned return					10.60%
Authorized return percentage					9.75%
South Carolina Regulation | Forecast
Public Utilities General Disclosures [Line Items]
One-time bill credit															$ 7
Materials and supplies inventory write down															$ 50
South Carolina Regulation | Electric Base Rate Case
Public Utilities General Disclosures [Line Items]
Percentage of earned return					4.32%
Percentage of proposed earned return					10.60%
Authorized return percentage					9.50%
South Carolina Regulation | Electric Base Rate Case | Subsequent Event
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement		$ 219
Approved return on equity percentage		9.94%
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Estimated under-recovered balances						$ 1,300
Virginia Electric and Power Company | Impairment of Assets and Other Charges
Public Utilities General Disclosures [Line Items]
Impairment of assets and other charges (benefits)													$ (17)
Impairment of assets and other charges (benefits) after tax													(12)
Virginia Electric and Power Company | Annual Fuel Factor
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement											$ (13)
Virginia Electric and Power Company | Utility Scale Solar
Public Utilities General Disclosures [Line Items]
Proposed cost of project									$ 850
Number of utility-scale projects | Project									4
Targeted capacity provided by legislation | MW									329
Virginia Electric and Power Company | Virginia LNG Storage Facility
Public Utilities General Disclosures [Line Items]
Liquefied equivalent | Bcf / d			2
Regasify storage capacity			25.00%
Liquefy storage capacity			1.00%
Facility expected cost, excluding financing costs			$ 550
Virginia Electric and Power Company | Virginia Regulation
Public Utilities General Disclosures [Line Items]
Public utilities event costs to be recovered								$ 45
Authorized return percentage						9.70%				9.70%
Capitalization ratio										52.10%
Virginia Electric and Power Company | Virginia Regulation | Forecast
Public Utilities General Disclosures [Line Items]
One-time credits to customers	$ 15
Virginia Electric and Power Company | Virginia Regulation | Base Rate Case
Public Utilities General Disclosures [Line Items]
Total revenue requirement										$ 350
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor
Public Utilities General Disclosures [Line Items]
Total revenue requirement				$ 2,200							$ 2,300
Rate year beginning				2024-07							2023-07
Increase (decrease) in revenue requirement				$ 636
Estimated under-recovered balances											$ 1,300
Estimated over-recovered balances												$ 266
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor | Securitization Option
Public Utilities General Disclosures [Line Items]
Estimated under-recovered balances											$ 1,300
Virginia Electric and Power Company | Virginia Regulation | Generation And Distribution Services
Public Utilities General Disclosures [Line Items]
Authorized return percentage								9.05%
Virginia Electric and Power Company | Biennial Review
Public Utilities General Disclosures [Line Items]
Authorized return percentage						0.70%
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric DSM Programs
Public Utilities General Disclosures [Line Items]
Public energy efficiency programs cost rate adjustment approval request to recover amount							$ 47
Dominion Energy South Carolina Inc | South Carolina Regulation | Cost of Fuel
Public Utilities General Disclosures [Line Items]
Rate year beginning						2024-05
Application date						2024-02
Proposed increase (decrease) in annual base fuel component recoveries														$ (315)
Increase (decrease) in annual base fuel component recoveries					$ (316)
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric Base Rate Case
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement					295
Increase (decrease) in net of storm damage					$ (4)
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric Base Rate Case | Forecast
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement	$ 291
Increase in proposed base rate percentage	12.59%
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric Transmission Project
Public Utilities General Disclosures [Line Items]
Application date					2024-03
Type of Line | kV					230
Miles of Lines | mi					7
Cost Estimate					$ 40								$ 40