v3.26.1
Fair Value Measurements (Financial Instruments' Carrying Amounts and Fair Values) (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Carrying Amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt [1] $ 41,786 $ 38,897
Securitization bonds [2] 970 1,054
Junior subordinated notes [1] 7,462 5,978
Estimate of Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt [1],[3] 39,944 37,481
Securitization bonds [2],[3] 974 1,076
Junior subordinated notes [1],[3] 7,682 6,217
Virginia Electric and Power Company | Carrying Amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt [1] 23,178 21,800
Securitization bonds [2] 970 1,054
Virginia Electric and Power Company | Estimate of Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt [1],[3] 21,725 20,593
Securitization bonds [2],[3] $ 974 $ 1,076
[1] Carrying amount includes current portions included in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium. There were no fair value hedges associated with fixed-rate debt at June 30, 2026 and December 31, 2025.
[2] Carrying amount includes current portions included in securities due within one year.
[3] Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.