Liability associated with its investment.

No definition available.

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Namespace Prefix:	d_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Unfunded commitments.

+ References

No definition available.

+ Details

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Namespace Prefix:	d_
Data Type:	xbrli:monetaryItemType
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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
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Balance Type:	na
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

Name:	srt_OwnershipAxis=d_DominionCovePointLNGLPMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=d_AtlanticCoastPipelineLLCMember
Namespace Prefix:
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Period Type:

- Details

Name:	srt_OwnershipAxis=d_FowlerIHoldingsLimitedLiabilityCompanyMember
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Investments (Investments Under Equity Method of Accounting) (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Nov. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Align RNG, LLC
Schedule of Equity Method Investments [Line Items]
Unfunded Commitments	$ 59
Cove Point
Schedule of Equity Method Investments [Line Items]
Ownership percentage		50.00%
Atlantic Coast Pipeline
Schedule of Equity Method Investments [Line Items]
Percentage ownership in total units	53.00%			48.00%
Liability associated with its investment	$ 1,100
Fowler Ridge
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest sold to noncontrolling interest owners			50.00%