XML 126 R116.htm IDEA: XBRL DOCUMENT
v3.24.3

Employee Benefit Plans (Narrative) (Detail) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Sep. 30, 2024 | Jun. 30, 2024 | Mar. 31, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2024 | Oct. 31, 2024
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Defined contribution plan operating expenses within discontinued operations |  |  | $ 23 |  |  |  |  |
Defined Contribution Plan Operating Expenses Within Discontinued Operations After Tax |  |  | 17 |  |  |  |  |
Defined contribution plan other operations and maintenance expense |  |  | 13 |  |  |  |  |
Defined contribution plan other operations and maintenance expense after tax |  |  | 10 |  |  |  |  |
Discontinued operations |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Service cost | $ 1 |  |  | $ 4 | $ 5 | $ 12 |  |
Non-service cost (credit) | (0) |  |  | (11) | 13 | (34) |  |
Other Postretirement Benefits Plan |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Service cost | 2 |  |  | 3 | 8 | 10 |  |
Decrease in the accumulated postretirement benefit obligation, transferred upon closing | (1) |  |  |  | (1) |  |  |
Defined benefit plan, loss on sale | 1 |  |  | 1 | 5 | 4 |  |
Other Postretirement Benefits Plan | Closure of East Ohio Transaction |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Increase in the fair value of the plan assets due to remeasurement |  | $ 24 | 19 |  |  |  |  |
Increase in the fair value of the plan assets, transferred upon closing |  | 5 | 36 |  |  |  |  |
Decrease in the accumulated postretirement benefit obligation |  | 14 | 38 |  |  |  |  |
Decrease in the accumulated postretirement benefit obligation, transferred upon closing |  | $ 6 | 22 |  |  |  |  |
Increase (decrease) in net periodic benefit credit |  |  | 1 |  |  |  |  |
Defined benefit plan, loss on sale |  |  | $ (9) |  |  |  |  |
Other Postretirement Benefits Plan | Questar Gas and Wexpro |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Remeasurement, discount rate |  | 5.74% |  |  |  |  |  |
Defined benefit plan, loss on sale |  | $ 1 |  |  |  |  |  |
Other Postretirement Benefits Plan | Forecast | Questar Gas and Wexpro |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Increase (decrease) in net periodic benefit credit |  |  |  |  |  |  | $ 3 |
Other Postretirement Benefits Plan | Minimum | Closure of East Ohio Transaction |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Remeasurement, discount rate |  |  | 5.61% |  |  |  |  |
Other Postretirement Benefits Plan | Maximum | Closure of East Ohio Transaction |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Remeasurement, discount rate |  |  | 5.62% |  |  |  |  |
Pension Benefits |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Contributions to qualified defined benefit pension plans | 33 |  |  |  | 40 |  |  |
Service cost | 19 |  |  | $ 24 | 63 | $ 72 |  |
Decrease in the accumulated postretirement benefit obligation, transferred upon closing |  |  |  |  | 4 |  |  |
Defined benefit plan, loss on sale | $ (3) |  |  |  | $ (16) |  |  |
Pension Benefits | Subsequent Event |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Additional employer contributions |  |  |  |  |  |  |  | $ 6
Pension Benefits | Closure of East Ohio Transaction |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Decrease in the pension benefit obligation due to remeasurement |  |  | $ 419 |  |  |  |  |
Decrease in the pension benefit obligation, amount transferred upon closing |  |  | 195 |  |  |  |  |
Increase in the fair value of the plan assets due to remeasurement |  |  | 555 |  |  |  |  |
Increase in the fair value of the plan assets, transferred upon closing |  |  | 531 |  |  |  |  |
Increase (decrease) in net periodic benefit credit |  |  | $ 11 |  |  |  |  |
Remeasurement, discount rate |  |  | 5.62% |  |  |  |  |
Defined benefit plan, loss on sale |  |  | $ 147 |  |  |  |  |
Pension Benefits | Questar Gas and Wexpro |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Decrease in the pension benefit obligation due to remeasurement |  | 251 |  |  |  |  |  |
Decrease in the pension benefit obligation, amount transferred upon closing |  | 136 |  |  |  |  |  |
Increase in the fair value of the plan assets due to remeasurement |  | 248 |  |  |  |  |  |
Increase in the fair value of the plan assets, transferred upon closing |  | $ 138 |  |  |  |  |  |
Remeasurement, discount rate |  | 5.75% |  |  |  |  |  |
Defined benefit plan, loss on sale |  | $ 49 |  |  |  |  |  |
Pension Benefits | Forecast | Questar Gas and Wexpro |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Increase (decrease) in net periodic benefit credit |  |  |  |  |  |  | $ 8 |

X
- Definition Defined benefit plan additional employer contributions. + References No definition available. + Details
Name: | d_DefinedBenefitPlanAdditionalEmployerContributions
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Defined benefit plan non service cost credit. + References No definition available. + Details
Name: | d_DefinedBenefitPlanNonServiceCostCredit
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined contribution plan operating expenses within discontinued operations. + References No definition available. + Details
Name: | d_DefinedContributionPlanOperatingExpensesWithinDiscontinuedOperations
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined contribution plan operating expenses within discontinued operations after tax. + References No definition available. + Details
Name: | d_DefinedContributionPlanOperatingExpensesWithinDiscontinuedOperationsAfterTax
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined contribution plan other operations and maintenance expense. + References No definition available. + Details
Name: | d_DefinedContributionPlanOtherOperationsAndMaintenanceExpense
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined contribution plan other operations and maintenance expense after tax. + References No definition available. + Details
Name: | d_DefinedContributionPlanOtherOperationsAndMaintenanceExpenseAfterTax
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in accumulated benefit obligation from change in existing term of defined benefit plan or initiation of new defined benefit plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (r) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAccumulatedBenefitObligationIncreaseDecreaseForPlanAmendment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of (increase) decrease in accumulated benefit obligation of defined benefit plan from effects of settlement and curtailment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (r) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAccumulatedBenefitObligationIncreaseDecreaseForSettlementAndCurtailment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480535/715-20-45-3A Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of increase (decrease) in plan assets of defined benefit plan from assets transferred into (from) plan. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanAssetsTransferredToFromPlan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of (increase) decrease to benefit obligation of defined benefit plan from remeasurement due to settlement. Excludes decrease to benefit obligation for settlement payment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(10) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanBenefitObligationIncreaseDecreaseForRemeasurementDueToSettlement
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in plan assets of defined benefit plan. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) in net periodic benefit cost from effect of change in substantive term of existing defined benefit plan or initiation of new defined benefit plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (r) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditIncreaseDecreaseForPlanAmendment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
Name: | us-gaap_DefinedBenefitPlanServiceCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) in obligation for pension benefits. Includes, but is not limited to, defined benefit or defined contribution plans. Excludes other postretirement benefits. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (a) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_IncreaseDecreaseInPensionPlanObligations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 25 -Subparagraph (g) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-25 + Details
Name: | us-gaap_PensionContributions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementOperatingActivitiesSegmentAxis=us-gaap_SegmentDiscontinuedOperationsMember
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_StatementBusinessSegmentsAxis=d_EastOhioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=d_QuestarGasAndWexproMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
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_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |