Regulatory Matters (Narrative) (Detail 4) $ in Millions	1 Months Ended												3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($)	Oct. 31, 2023 USD ($) MW	Jul. 31, 2023 USD ($)	May 31, 2023 USD ($)	Apr. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Feb. 28, 2023 USD ($)	Oct. 31, 2022 MW	May 31, 2022 USD ($)	Oct. 31, 2021 USD ($)	Apr. 30, 2020 MW	Dec. 31, 2011	Mar. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2008
Target to Reach by End of 2025
Public Utilities, General Disclosures [Line Items]
Energy efficiency target percentage. based on energy savings from 2019 baseline											5.00%
Virginia Regulation
Public Utilities, General Disclosures [Line Items]
Authorized return percentage			9.35%
North Carolina Regulation
Public Utilities, General Disclosures [Line Items]
Approval date						2023-03
Ohio Regulation | Base Rate Case
Public Utilities, General Disclosures [Line Items]
Percentage of proposed earned return		10.40%
Increase (Decrease) in non-fuel base rate		$ 212
Authorized return percentage		10.38%
Ohio Regulation | PIR Program
Public Utilities, General Disclosures [Line Items]
Total revenue requirement																$ 305
Approval date of application															2023-04
Percentage of pipeline system replaced																	25.00%
Total gross plant investment estimated cost																225
Cumulative gross plant investment estimated cost																$ 2,400
Increases of annual capital expenditures percentage					3.00%
Ohio Regulation | CEP Program
Public Utilities, General Disclosures [Line Items]
Total revenue requirement															$ 151
Total gross plant investment estimated cost	$ 195														195
Cumulative gross plant investment estimated cost	1,300														$ 1,300
Percentage of debt rate on capital investments												6.50%
Application date															2023-09
Ohio Regulation | UEX Rider
Public Utilities, General Disclosures [Line Items]
Actual revenue requirement															$ 23
Public utilities, under-recovered accumulated bad debt expense													$ 9
Ohio Regulation | Forecast | UEX Rider
Public Utilities, General Disclosures [Line Items]
Recovery of bad debt expense														$ 14
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]
Targeted capacity provided by legislation | MW		329						474
Virginia Electric and Power Company | Virginia Regulation
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement										$ 330
Authorized return percentage			9.70%		9.70%
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement									$ 1,800
Total revenue requirement				2,300					2,300
Virginia Electric and Power Company | Virginia Regulation | Base Rate Case
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement										$ 50
Authorized return percentage										9.35%
Total revenue requirement			$ 350	$ 351	$ 350
Virginia Electric and Power Company | Virginia Regulation | Maximum | Annual Fuel Factor
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement									1,300
Virginia Electric and Power Company | Virginia Regulation | Minimum | Annual Fuel Factor
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement									$ 1,200
Virginia Electric and Power Company | Virginia Regulation | Offshore Wind Facility | End of Year 2035 | Maximum
Public Utilities, General Disclosures [Line Items]
Constructed by utility capacity | MW											3,000
Virginia Electric and Power Company | Virginia Regulation | Offshore Wind Facility | End of Year 2035 | Minimum
Public Utilities, General Disclosures [Line Items]
Constructed by utility capacity | MW											2,500
Virginia Electric and Power Company | Virginia Regulation | Offshore Wind Facility | Before 2035 | Maximum
Public Utilities, General Disclosures [Line Items]
Targeted capacity provided by legislation | MW											5,200
Virginia Electric and Power Company | Virginia Regulation | Utility-scale Solar | End of Year 2035 | Maximum
Public Utilities, General Disclosures [Line Items]
Targeted capacity provided by legislation | MW											15,000
Virginia Electric and Power Company | Virginia Regulation | Pumped Storage | End of Year 2035 | Maximum
Public Utilities, General Disclosures [Line Items]
Targeted capacity provided by legislation | MW											800
Questar Gas Company | Utah Regulation
Public Utilities, General Disclosures [Line Items]
Approval date							2023-02
Increase (decrease) in gas cost						$ 92	$ 164
Percentage of adjustments of distribution non-gas revenues															5.00%
Decrease in non-gas cost	$ 27