XML 166 R140.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Employee Benefit Plans (Fair values of pension and post retirement plan assets by asset category) (Detail) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total investments |  | $ 1,378 | $ 1,078 |
Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total investments |  | 1,828 | 1,557 |
Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 8,062 | 7,016 | $ 6,166
Pension Benefits | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,803 | 1,542 | 1,467
Other Postretirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,729 | 1,512 | 1,382
Other Postretirement Benefits | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 333 | 299 | $ 283
Collective Bargaining Agreement | Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 4,878 | 4,233 |
Total recorded at NAV | [1] | 3,169 | 2,765 |
Total investments | [2] | 8,047 | 6,998 |
Collective Bargaining Agreement | Pension Benefits | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,090 | 930 |
Total recorded at NAV | [1] | 709 | 608 |
Total investments | [3] | 1,799 | 1,538 |
Collective Bargaining Agreement | Pension Benefits | Common/collective trust funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 2,272 | 1,960 |
Collective Bargaining Agreement | Pension Benefits | Common/collective trust funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 509 | 430 |
Collective Bargaining Agreement | Pension Benefits | Cash equivalents and other |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 18 | 14 |
Collective Bargaining Agreement | Pension Benefits | Cash equivalents and other | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 4 | 3 |
Collective Bargaining Agreement | Pension Benefits | Equity securities: | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,902 | 1,705 |
Collective Bargaining Agreement | Pension Benefits | Equity securities: | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,151 | 928 |
Collective Bargaining Agreement | Pension Benefits | Equity securities: | Dominion Energy Gas Holdings, LLC | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 425 | 375 |
Collective Bargaining Agreement | Pension Benefits | Equity securities: | Dominion Energy Gas Holdings, LLC | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 257 | 203 |
Collective Bargaining Agreement | Pension Benefits | Insurance contracts |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 352 | 334 |
Collective Bargaining Agreement | Pension Benefits | Insurance contracts | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 79 | 73 |
Collective Bargaining Agreement | Pension Benefits | Corporate debt instruments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 770 | 717 |
Collective Bargaining Agreement | Pension Benefits | Corporate debt instruments | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 172 | 158 |
Collective Bargaining Agreement | Pension Benefits | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 685 | 535 |
Collective Bargaining Agreement | Pension Benefits | Government securities | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 153 | 118 |
Collective Bargaining Agreement | Pension Benefits | Real Estate Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 111 | 121 |
Collective Bargaining Agreement | Pension Benefits | Real Estate Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 25 | 27 |
Collective Bargaining Agreement | Pension Benefits | Private Equity Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 606 | 506 |
Collective Bargaining Agreement | Pension Benefits | Private Equity Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 135 | 111 |
Collective Bargaining Agreement | Pension Benefits | Fixed Income Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 161 | 153 |
Collective Bargaining Agreement | Pension Benefits | Fixed Income Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 36 | 34 |
Collective Bargaining Agreement | Pension Benefits | Hedge Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 19 | 25 |
Collective Bargaining Agreement | Pension Benefits | Hedge Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 4 | 6 |
Collective Bargaining Agreement | Pension Benefits | Level 1 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 3,121 | 2,693 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 697 | 592 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Cash equivalents and other |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 18 | 12 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Cash equivalents and other | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 4 | 3 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Equity securities: | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,902 | 1,705 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Equity securities: | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,151 | 928 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Equity securities: | Dominion Energy Gas Holdings, LLC | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 425 | 375 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Equity securities: | Dominion Energy Gas Holdings, LLC | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 257 | 203 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Corporate debt instruments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 41 | 35 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Corporate debt instruments | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 9 | 8 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 9 | 13 |
Collective Bargaining Agreement | Pension Benefits | Level 1 | Government securities | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 2 | 3 |
Collective Bargaining Agreement | Pension Benefits | Level 2 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1,757 | 1,540 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 393 | 338 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Cash equivalents and other |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  |  | 2 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Insurance contracts |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 352 | 334 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Insurance contracts | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 79 | 73 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Corporate debt instruments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 729 | 682 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Corporate debt instruments | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 163 | 150 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 676 | 522 |
Collective Bargaining Agreement | Pension Benefits | Level 2 | Government securities | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 151 | 115 |
Collective Bargaining Agreement | Other Postretirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 944 | 808 |
Total recorded at NAV | [1] | 783 | 702 |
Total investments | [4] | 1,727 | 1,510 |
Collective Bargaining Agreement | Other Postretirement Benefits | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 163 | 145 |
Total recorded at NAV | [1] | 170 | 154 |
Total investments |  | 333 | 299 |
Collective Bargaining Agreement | Other Postretirement Benefits | Common/collective trust funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 689 | 621 |
Collective Bargaining Agreement | Other Postretirement Benefits | Common/collective trust funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 154 | 140 |
Collective Bargaining Agreement | Other Postretirement Benefits | Cash equivalents and other |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 3 | 2 |
Collective Bargaining Agreement | Other Postretirement Benefits | Equity securities: | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 636 | 571 |
Collective Bargaining Agreement | Other Postretirement Benefits | Equity securities: | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 196 | 143 |
Collective Bargaining Agreement | Other Postretirement Benefits | Equity securities: | Dominion Energy Gas Holdings, LLC | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 130 | 121 |
Collective Bargaining Agreement | Other Postretirement Benefits | Equity securities: | Dominion Energy Gas Holdings, LLC | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 33 | 24 |
Collective Bargaining Agreement | Other Postretirement Benefits | Insurance contracts |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 21 | 19 |
Collective Bargaining Agreement | Other Postretirement Benefits | Corporate debt instruments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 46 | 42 |
Collective Bargaining Agreement | Other Postretirement Benefits | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 42 | 31 |
Collective Bargaining Agreement | Other Postretirement Benefits | Real Estate Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 9 | 9 |
Collective Bargaining Agreement | Other Postretirement Benefits | Real Estate Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 1 | 1 |
Collective Bargaining Agreement | Other Postretirement Benefits | Private Equity Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 73 | 59 |
Collective Bargaining Agreement | Other Postretirement Benefits | Private Equity Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 15 | 12 |
Collective Bargaining Agreement | Other Postretirement Benefits | Fixed Income Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 11 | 12 |
Collective Bargaining Agreement | Other Postretirement Benefits | Fixed Income Funds | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] |  | 1 |
Collective Bargaining Agreement | Other Postretirement Benefits | Hedge Funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at NAV | [1] | 1 | 1 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 836 | 718 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Dominion Energy Gas Holdings, LLC |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 163 | 145 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Cash equivalents and other |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1 | 1 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Equity securities: | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 636 | 571 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Equity securities: | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 196 | 143 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Equity securities: | Dominion Energy Gas Holdings, LLC | U.S. |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 130 | 121 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Equity securities: | Dominion Energy Gas Holdings, LLC | International |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 33 | 24 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Corporate debt instruments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 2 | 2 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 1 | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 1 | 1 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 2 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 108 | 90 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 2 | Cash equivalents and other |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 2 | 1 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 2 | Insurance contracts |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 21 | 19 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 2 | Corporate debt instruments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | 44 | 40 |
Collective Bargaining Agreement | Other Postretirement Benefits | Level 2 | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Total recorded at fair value |  | $ 41 | $ 30 |
[1] | These investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient which are not required to be categorized in the fair value hierarchy.
[2] | Excludes net assets related to pending sales of securities of $11 million, net accrued income of $19 million, and includes net assets related to pending purchases of securities of $15 million at December 31, 2017. Excludes net assets related to pending sales of securities of $46 million, net accrued income of $19 million, and includes net assets related to pending purchases of securities of $47 million at December 31, 2016.
[3] | Excludes net assets related to pending sales of securities of $3 million, net accrued income of $4 million, and includes net assets related to pending purchases of securities of $3 million at December 31, 2017. Excludes net assets related to pending sales of securities of $10 million, net accrued income of $4 million, and includes net assets related to pending purchases of securities of $10 million at December 31, 2016.
[4] | Excludes net assets related to pending sales of securities of $1 million, net accrued income of $2 million, and includes net assets related to pending purchases of securities of $1 million at December 31, 2017. Excludes net assets related to pending sales of securities of $5 million, net accrued income of $2 million, and includes net assets related to pending purchases of securities of $5 million at December 31, 2016.

X
- Definition Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets + References No definition available. + Details
Name: | d_DefinedBenefitPlanAlternativeInvestmentsFairValueOfPlanAssets
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64852052&loc=d3e1731-114919 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(17)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64852052&loc=d3e1703-114919 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(10)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=d_DominionEnergyGasHoldingsLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=d_CollectiveBargainingAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_TrustForBenefitOfEmployeesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=d_InsuranceContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_FixedIncomeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_HedgeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |