Acquisitions and Dispositions (Disposition of Gas Transmission & Storage Operations to BHE) (Narrative) (Detail) - Gas, Transmission & Storage - BHE - USD ($) $ in Millions	3 Months Ended
Sep. 30, 2020	Jul. 31, 2020
Dominion Energy \| Scenario Forecast
Business Acquisition And Dispositions [Line Items]
Expect to record pre-tax losses	$ 225
Dominion Energy Gas Holdings, LLC \| Scenario Forecast
Business Acquisition And Dispositions [Line Items]
Expect to record pre-tax losses	$ 140
Dominion Energy Gas Holdings, LLC \| Subsequent Event
Business Acquisition And Dispositions [Line Items]
Disposal group, total value of consideration		$ 10,000
Disposal group, cash consideration		$ 4,000
Percentage ownership in total units		50.00%
Disposal group, expects to recognize pre-tax gain upon closing		$ 1,000
Disposal group, decrease in cash consideration		$ 2,700
Dominion Energy Gas Holdings, LLC \| General Partner Interest \| Subsequent Event
Business Acquisition And Dispositions [Line Items]
Percentage ownership in total units		100.00%
Dominion Energy Gas Holdings, LLC \| Limited Partner Interests \| Subsequent Event
Business Acquisition And Dispositions [Line Items]
Percentage ownership in total units		25.00%

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- Definition

Discontinued operation gain loss from disposal of discontinued operation including cash flow hedges before income tax.

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- Definition

Disposal group including discontinued operation decrease in cash consideration.

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- Definition

The excess amount received or due over net assets in a transaction accounted for as a divestiture where a subsidiary, business or operating assets are "sold" by the entity to a newly formed, thinly capitalized, highly leveraged buyer. This gain is not yet recognized and is disclosed on the balance sheet as an offset against the carrying amount of the securities received.

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Amount of currency on hand, demand deposits with banks or financial institutions, and other kinds of accounts that have the general characteristics of demand deposits, held by a disposal group.

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- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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