v3.26.3
Operating Segments - Dominion Energy (Narrative) (Detail)
$ in Millions
 9 Months Ended
Sep. 30, 2026
USD ($)
Segment
Sep. 30, 2025
USD ($)
Segment Reporting Information [Line Items]    
Number of operating segment | Segment 3  
Number of reportable segment | Segment 3  
Gains (loss) on investments $ 453 $ 442
Virginia Electric and Power Company    
Segment Reporting Information [Line Items]    
Number of operating segment | Segment 1  
Number of reportable segment | Segment 1  
Gains (loss) on investments $ 58 65
Operating Segments    
Segment Reporting Information [Line Items]    
After- tax net benefits (expenses) (572) 81
Gains (loss) on investments 438 415
Gains (loss) on investments, after tax $ 293 $ 255
Investment, Type [Extensible Enumeration] Nuclear Decommissioning Trust Fund [Member] Nuclear Decommissioning Trust Fund [Member]
Operating Segments | Virginia Electric and Power Company    
Segment Reporting Information [Line Items]    
Gains (loss) on investments $ 63 $ 59
Gains (loss) on investments, after tax $ 37 $ 34
Investment, Type [Extensible Enumeration] Nuclear Decommissioning Trust Fund [Member] Nuclear Decommissioning Trust Fund [Member]
Share of costs not expected to be recovered from customers on the CVOW commercial project $ 65 $ 112
Share of costs not expected to be recovered from customers on the CVOW commercial project, after tax 48 84
Loss associated with severe weather events 119 106
Loss associated with severe weather events, after-tax 88 79
Charge for the disallowance of certain strategic undergrounding costs 24  
Charge for the disallowance of certain strategic undergrounding costs, net of tax 18  
Corporate and Other | Operating Segments    
Segment Reporting Information [Line Items]    
After- tax net benefits (expenses) (826) (108)
After- tax net benefits (expenses) for specific items (577) 58
Corporate and Other | Operating Segments | Virginia Electric and Power Company    
Segment Reporting Information [Line Items]    
After- tax net benefits (expenses) (102) (101)
After- tax net benefits (expenses) for specific items (126) (127)
Contracted Energy | Operating Segments    
Segment Reporting Information [Line Items]    
Gains (loss) on investments, after tax 256 221
Gain (losses) related to economic hedging activities (172) (16)
Gain (losses) related to economic hedging activities after tax (129) (12)
Charge associated with certain nonregulated solar generation facilities 79  
Charge associated with certain nonregulated solar generation facilities, net of tax 61  
Charge for the termination of certain supply contracts associated with renewable natural gas operations 14  
Charge for the termination of certain supply contracts associated with renewable natural gas operations after tax 11  
Charge for the impairment of nonregulated renewable natural gas facilities 820  
Charge for the impairment of nonregulated renewable natural gas facilities, net of tax 640  
Benefit related to the revision of aros for millstone unit 195  
Benefit related to the revision of aros for millstone unit 1, after tax 142  
Dominion Energy Virginia | Operating Segments    
Segment Reporting Information [Line Items]    
Gains (loss) on investments, after tax $ 37 $ 34
Investment, Type [Extensible Enumeration] Nuclear Decommissioning Trust Fund [Member] Nuclear Decommissioning Trust Fund [Member]
Share of costs not expected to be recovered from customers on the CVOW commercial project $ 65 $ 112
Share of costs not expected to be recovered from customers on the CVOW commercial project, after tax 48 84
Loss associated with severe weather events 119 106
Loss associated with severe weather events, after-tax 88 $ 79
Charge for the disallowance of certain strategic undergrounding costs 24  
Charge for the disallowance of certain strategic undergrounding costs, net of tax $ 18