Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

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Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

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- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

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Period Type:	duration

- 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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- Details

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- Details

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- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_PartnershipInterestMember
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- Details

Name:	us-gaap_StatementClassOfStockAxis=d_CommonAndSubordinatedUnitsMember
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- Details

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- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
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- Details

Name:	dei_LegalEntityAxis=d_VirginiaElectricAndPowerCompanyMember
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Nature of Operations (Narrative) (Detail)	1 Months Ended		12 Months Ended
Nature of Operations (Narrative) (Detail)	Sep. 30, 2015 shares	Oct. 31, 2014 shares	Dec. 31, 2017 Segments
Subsidiary, Sale of Stock [Line Items]
Number of operating segments			3
Dominion Energy Midstream Partners, LP \| Iroquois \| Partnership Interest
Subsidiary, Sale of Stock [Line Items]
Common units included in initial public offering \| shares	8,600,000
Noncontrolling partnership percentage interest			25.93%
Dominion Energy Midstream Partners, LP \| Common and Subordinated Units
Subsidiary, Sale of Stock [Line Items]
Ownership interest percentage of limited partner interests			50.60%
Dominion Energy Midstream Partners, LP \| Convertible Preferred Units
Subsidiary, Sale of Stock [Line Items]
Ownership interest percentage of limited partner interests			37.50%
Dominion Energy Midstream Partners, LP \| IPO [Member]
Subsidiary, Sale of Stock [Line Items]
Common units included in initial public offering \| shares		20,125,000
Virginia Electric and Power Company
Subsidiary, Sale of Stock [Line Items]
Number of operating segments			2
Dominion Energy Gas Holdings, LLC
Subsidiary, Sale of Stock [Line Items]
Number of operating segments			1