Asset Impairment Charges After Tax

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Capacity of facility of company owned solar distribution generation facilities.

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- Definition

Increase Decrease In Earnings Per Share

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Number of facilities in cold reserve units retired.

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[Line Items] for Significant Accounting Policies [Table]

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Utilities operating expense, increase (decrease) in depreciation and amortization.

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Utilities operating expense, increase (decrease) in depreciation and amortization, after tax.

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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

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Significant Accounting Policies (Narrative) (Detail) $ / shares in Units, $ in Millions	1 Months Ended			3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($) Facility MW	Jan. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) $ / shares	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) $ / shares
Significant Accounting Policies [Line Items]
Impairment of assets and other charges				$ 768	$ 835
Change in Estimated Useful Life \| Merchant generation assets \| Scenario Forecast
Significant Accounting Policies [Line Items]
Increase in EPS \| $ / shares						$ 0.03
Virginia Electric and Power Company
Significant Accounting Policies [Line Items]
Impairment of assets and other charges				764	$ 546
MW Capacity \| MW		1,292
Number of facilities in cold reserve units retired \| Facility		6
Virginia Electric and Power Company \| Change In Depreciation Rates From New Depreciation Study
Significant Accounting Policies [Line Items]
Increase (decrease) in depreciation expense				(8)
Increase (decrease) in depreciation expense, after tax				$ (6)
Increase in EPS \| $ / shares				$ 0.01
Virginia Electric and Power Company \| Change in Estimated Useful Life \| Merchant generation assets \| Scenario Forecast
Significant Accounting Policies [Line Items]
Increase (decrease) in depreciation expense						$ (31)
Increase (decrease) in depreciation expense, after tax						$ (23)
Virginia Electric and Power Company \| Impairment of Assets and Other Charges
Significant Accounting Policies [Line Items]
Impairment of assets and other charges	$ 754	$ 369	$ 160
Asset impairment charges after tax	$ 561	$ 275	$ 119
Dominion Energy Midstream Partners, LP \| Terra Nova Renewable Partners \| Merchant Solar Projects \| Call Option
Significant Accounting Policies [Line Items]
Percentage ownership in total units	67.00%			67.00%
Dominion Energy Midstream Partners, LP \| Dominion Energy Gas Holdings, LLC
Significant Accounting Policies [Line Items]
Percentage of equity interest sold to noncontrolling interest owners	25.00%			25.00%
Four Brothers and Three Cedars
Significant Accounting Policies [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	50.00%			50.00%
Four Brothers and Three Cedars \| Dominion Energy Midstream Partners, LP \| Terra Nova Renewable Partners \| Merchant Solar Projects
Significant Accounting Policies [Line Items]
Percentage of equity interest sold to noncontrolling interest owners	33.00%			33.00%