Related-Party Transactions (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Services provided to affiliates		$ 3,632	$ 3,883
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Commodity purchases from affiliates		198	214
Services provided to affiliates	[1]	2,489	2,384
Virginia Electric and Power Company | Related Party
Related Party Transaction [Line Items]
Services provided by affiliates	[2]	155	147
Services provided to affiliates		$ 4	$ 4

[1] See Note 19 for amounts attributable to affiliates.

[2] Includes capitalized expenditures of $53 million and $54 million for the three months ended March 31, 2024 and 2023, respectively.