v3.26.1
Operating Segments - Virginia Power (Narrative) (Detail) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]    
Gains (loss) on investments $ 350 $ 173
Operating Segments    
Segment Reporting Information [Line Items]    
After- tax net income (expenses) (607) (7)
Gains (loss) on investments 341 156
Gains (loss) on investments, after tax $ 221 $ 87
Investment, Type [Extensible Enumeration] Nuclear Decommissioning Trust Fund [Member] Nuclear Decommissioning Trust Fund [Member]
Operating Segments | Corporate and Other    
Segment Reporting Information [Line Items]    
After- tax net income (expenses) $ (760) $ (102)
After- tax net income (expenses) for specific items (598) (27)
Virginia Electric and Power Company    
Segment Reporting Information [Line Items]    
Gains (loss) on investments 48 24
Virginia Electric and Power Company | Operating Segments    
Segment Reporting Information [Line Items]    
Loss associated with severe weather events 116 106
Loss associated with severe weather events, after-tax 86 79
Share of costs not expected to be recovered from customers on the CVOW commercial project 65 48
Share of costs not expected to be recovered from customers on the CVOW commercial project, after tax 48 36
Charge for the disallowance of certain strategic undergrounding costs 24  
Charge for the disallowance of certain strategic undergrounding costs, net of tax 18  
Gains (loss) on investments 53 23
Gains (loss) on investments, after tax $ 31 $ 13
Investment, Type [Extensible Enumeration] Nuclear Decommissioning Trust Fund [Member] Nuclear Decommissioning Trust Fund [Member]
Virginia Electric and Power Company | Operating Segments | Corporate and Other    
Segment Reporting Information [Line Items]    
After- tax net income (expenses) $ (120) $ (90)
After- tax net income (expenses) for specific items $ (129) $ (100)