v3.26.3
Derivatives and Hedge Accounting Activities (Selected Information Related to Gains (Losses) on Cash Flow Hedges Included in AOCI) (Detail)
$ in Millions
9 Months Ended
Sep. 30, 2026
USD ($)
Derivative Instruments Gain Loss [Line Items]  
AOCI After-Tax $ (53)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax (21)
Virginia Electric and Power Company  
Derivative Instruments Gain Loss [Line Items]  
AOCI After-Tax 61
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax 1
Interest Rate Contract  
Derivative Instruments Gain Loss [Line Items]  
AOCI After-Tax (53)
Interest rate, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax $ (21)
Maximum Term 399 months
Interest Rate Contract | Virginia Electric and Power Company  
Derivative Instruments Gain Loss [Line Items]  
AOCI After-Tax $ 61
Interest rate, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax $ 1
Maximum Term 399 months