Commitments and Contingencies (SCANA Legal Proceedings) (Narrative) (Detail) - USD ($) shares in Millions, $ in Millions	1 Months Ended									3 Months Ended								12 Months Ended
	Jul. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	May 31, 2022	Aug. 31, 2021	Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2018	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Impairment of assets and other charges																		$ 307	$ 1,401	$ 194
Gain on sales of assets																		27	(426)	(415)
Gain on sales of assets after tax										$ 344	$ 698	$ 415	$ 700	$ 222	$ 585	$ (659)	$ 279	2,157	427	2,061
SCDOR | Corporate and Other
Loss Contingencies [Line Items]
Gain upon completion of remaining transfer of utility properties												$ 11
Fair value of utility property transferred													$ 10
Utility Property Transferred | SCDOR | Corporate and Other
Loss Contingencies [Line Items]
Gain on sales of assets																		9
Gain on sales of assets after tax																		7
Remaining Utility Property Transferred | SCDOR | Corporate and Other
Loss Contingencies [Line Items]
Gain on sales of assets																		11
Gain on sales of assets after tax																		$ 8
Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Litigation settlement paid			$ 51					$ 165
Proposed assessment amount from audit									$ 410
Proportional share of NND project									100.00%
Fair value of certain non-utility property transferred		$ 28
Gain on sales of assets																			18
Gain on sales of assets after tax																			14
Fair value of additional utility property transferred														3					3
Minimum | Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Initial litigation settlement amount through stock issuance							$ 43
Maximum | Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Payment For Remaining Obligation	$ 1
SCANA
Loss Contingencies [Line Items]
Cash payment			2
Impairment of assets and other charges																				100
Impairment of assets and other charges, after tax																				$ 75
Utilization of insurance proceeds for settlements			$ 33
Litigation settlement amount through stock issuance			0.4
SCANA | Other Current Liabilities
Loss Contingencies [Line Items]
Reserves for SCANA legal proceedings														94					94
SCANA | Other Receivables
Loss Contingencies [Line Items]
Insurance receivables														68					68
SCANA | Personal Injury or Wrongful Death Cases
Loss Contingencies [Line Items]
Reserves for SCANA legal proceedings														68					68
Insurance receivables														$ 68					$ 68
SCANA | State Court Derivative Case
Loss Contingencies [Line Items]
Litigation settlement paid							33
SCANA | Federal Court Merger Case | State Court Merger Case
Loss Contingencies [Line Items]
Litigation settlement paid							$ 63
DESC
Loss Contingencies [Line Items]
Litigation settlement expense						$ 99
DESC | Common Stock | Dominion Energy South Carolina Inc
Loss Contingencies [Line Items]
Litigation settlement through stock issuance						1.4
DESC | Common Stock | Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Initial litigation settlement through stock issuance				0.9	0.6