Operating Revenue (Schedule of Aggregate Amount of Transaction Price Allocated To Fixed-price Performance Obligations That Unsatisfied At End of Reporting Period And Expected To be Recognized) (Detail1) $ in Millions	Mar. 31, 2023 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, expected to be recognized on multi-year contracts	$ 662	[1]

[1] Includes no amounts for Virginia Power