Operating Revenue (Schedule of Operating Revenue) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	$ 4,456	$ 3,718	$ 9,547	$ 7,803
Renewable Energy Investment Tax Credits
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	27	5	50	15
Transition services agreements
Public Utilities General Disclosures [Line Items]
Other revenues	21	24	48	51
Alternative Revenue Programs
Public Utilities General Disclosures [Line Items]
Other revenues	90	60	136	82
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	3,326	2,660	6,974	5,411
Virginia Electric and Power Company \| Renewable Energy Investment Tax Credits
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers	6	2	11	6
Virginia Electric and Power Company \| Alternative Revenue Programs
Public Utilities General Disclosures [Line Items]
Other revenues	$ 90	$ 60	$ 136	$ 82

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details