XML 175 R152.htm IDEA: XBRL DOCUMENT
v3.20.4

Short-Term Debt and Credit Agreements (Narrative) (Detail) - USD ($) | 1 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
May 31, 2020 | Apr. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2020 | Oct. 31, 2020 | Dec. 31, 2019 | Nov. 30, 2017
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity | [2] |  |  |  | $ 6,000,000,000 | [1] |  | $ 6,000,000,000 |
Short-term debt |  |  |  |  | 895,000,000 |  |  | 849,000,000 |
Letter of Credit |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  | 2,000,000,000.0 |  |  |  |
364-Day Revolving Credit Facility |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  | $ 900,000,000 |  |  |  |  |
Credit facility, amount borrowed |  |  |  |  | $ 225,000,000 |  |  |  |
Weighted average useful life |  |  |  | 364 days |  |  |  |  |
Credit Facility, Maturing in June 2020 | Letter of Credit |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  | $ 30,000,000 | $ 21,000,000 |  |  |  |  |  |
Credit facility, maturity date |  | Jun. 30, 2022 |  |  | Jun. 30, 2020 |  |  |  |
Credit facility, amount borrowed |  |  |  |  | $ 30,000,000 |  |  | 21,000,000 |
Term Loan Credit Agreement |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Credit facility, amount borrowed |  |  | $ 625,000,000 | $ 500,000,000 |  |  |  |  |
Weighted average useful life |  |  | 364 days | 364 days |  |  |  |  |
Floating Rate Demand Notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Short-term debt |  |  |  |  | 268,000,000 |  |  | 75,000,000 |
Floating Rate Demand Notes | Shelf Registration for Sale of Demand Notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  |  |  |  |  | $ 3,000,000,000.0
Debt instrument, maximum principal outstanding amount |  |  |  |  |  |  | $ 1,000,000,000.0 |  |
Dominion Energy South Carolina Inc |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  | 500,000,000 |  |  |  |
Short-term indebtedness outstanding |  |  |  |  | $ 2,200,000,000 |  |  |  |
Debt maturity month and year |  |  |  |  | 2021-03 |  |  |  |
Questar Gas |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  | $ 250,000,000 |  |  |  |
GENCO |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Short-term indebtedness outstanding |  |  |  |  | $ 200,000,000 |  |  |  |
Debt maturity month and year |  |  |  |  | 2021-03 |  |  |  |
SBL Holdco | Credit Facilities, Maturing in December 2017 with 1 year Automatic Renewals through 2023 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  | $ 30,000,000 |  |  |  |
Automatic renewal period |  |  |  |  | 1 year |  |  |  |
Short-term debt |  |  |  |  | $ 0 |  |  | 0 |
Dominion Solar Projects III, Inc | Credit Facilities, Maturing in May 2018 with 1 year Automatic Renewals through 2024 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  | $ 25,000,000 |  |  |  |
Automatic renewal period |  |  |  |  | 1 year |  |  |  |
Short-term debt |  |  |  |  | $ 0 |  |  | $ 0 |
[1] | In October 2020, the joint revolving credit facility was amended to remove Dominion Energy Gas as a co-borrower.
[2] | This credit facility matures in March 2023 and can be used by the borrowers under the credit facility to support bank borrowings and the issuance of commercial paper, as well as to support up to a combined $2.0 billion of letters of credit.

X
- Definition Debt instrument auto renewal term. + References No definition available. + Details
Name: | d_DebtInstrumentAutoRenewalTerm
Namespace Prefix: | d_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt instrument maturity month and year. + References No definition available. + Details
Name: | d_DebtInstrumentMaturityMonthAndYear
Namespace Prefix: | d_
Data Type: | xbrli:gYearMonthItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt instrument maximum principal outstanding amount. + References No definition available. + Details
Name: | d_DebtInstrumentMaximumPrincipalOutstandingAmount
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date the credit facility terminates, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(a)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(1)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_ShortTermBorrowings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, the maximum amount borrowed at any time during the period. + References No definition available. + Details
Name: | us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=d_ThreeSixtyFourDayRevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=d_CreditFacilityMaturingInJuneTwoThousandTwentyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=d_TermLoanCreditAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=d_FloatingRateDemandNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=d_ShelfRegistrationForSaleOfDemandNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_DebtInstrumentAxis=d_CreditFacilitiesMaturingInDecember2017With1YearAutomaticRenewalsThrough2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_DebtInstrumentAxis=d_CreditFacilitiesMaturingInMay2018With1YearAutomaticRenewalsThrough2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |