Commitments and Contingencies (SCANA Legal Proceedings) (Narrative) (Detail) - USD ($) shares 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	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2018	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Gain on sales of assets																	$ 1,000,000	$ 27,000,000	$ (412,000,000)
Gain on sales of assets after tax									$ 95,000,000	$ 973,000,000	$ 483,000,000	$ 323,000,000	$ 364,000,000	$ 694,000,000	$ 407,000,000	$ 691,000,000	$ 1,874,000,000	2,156,000,000	269,000,000
SCDOR | Corporate and Other
Loss Contingencies [Line Items]
Gain upon completion of remaining transfer of utility properties															$ 11,000,000
Fair value of utility property transferred																$ 10,000,000
Utility Property Transferred | SCDOR | Corporate and Other
Loss Contingencies [Line Items]
Gain on sales of assets																		9,000,000
Gain on sales of assets after tax																		7,000,000
Remaining Utility Property Transferred | SCDOR | Corporate and Other
Loss Contingencies [Line Items]
Gain on sales of assets																		11,000,000
Gain on sales of assets after tax																		$ 8,000,000
Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Litigation settlement paid			$ 51,000,000				$ 165,000,000
Proposed assessment amount from audit								$ 410,000,000
Proportional share of NND project								100.00%
Fair value of certain non-utility property transferred		$ 28,000,000
Gain on sales of assets																			18,000,000
Gain on sales of assets after tax																			14,000,000
Fair value of additional utility property transferred																			$ 3,000,000
Minimum | Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Initial litigation settlement amount through stock issuance						$ 43,000,000
Maximum | Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Cash payment for remaining obligation	$ 1,000,000
SCANA
Loss Contingencies [Line Items]
Cash payment			2,000,000
Utilization of insurance proceeds for settlements			$ 33,000,000
Litigation settlement amount through stock issuance			0.4
SCANA | State Court Derivative Case
Loss Contingencies [Line Items]
Litigation settlement paid						33,000,000
SCANA | Federal Court Merger Case | State Court Merger Case
Loss Contingencies [Line Items]
Litigation settlement paid						$ 63,000,000
DESC | Common Stock | Dominion Energy South Carolina Inc | SCDOR
Loss Contingencies [Line Items]
Initial litigation settlement through stock issuance				0.9	0.6