 | us-gaap:StrandedCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredProjectCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:RecoverableVacationPayMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:StormCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:AssetImpairmentForRegulatoryActionMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredFuelCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:EnvironmentalRestorationCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:AssetRetirementObligationCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:LossOnReacquiredDebtMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredLossOnEarlyExtinguishmentOfDebtMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredIncomeTaxChargesMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:PensionCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:PostretirementBenefitCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:AssetRecoverableGasCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:NaturalGasTransitionCostMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:RegulatoryClauseRevenuesUnderRecoveredMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:OtherRegulatoryAssetsLiabilitiesMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:RemovalCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:PensionAndOtherPostretirementPlansCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredDerivativeGainLossMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:RenewableEnergyProgramMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:AdvancedMeteringInfrastructureCostsMember | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:StrandedCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:DeferredProjectCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:RecoverableVacationPayMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:StormCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:AssetImpairmentForRegulatoryActionMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:DeferredFuelCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:EnvironmentalRestorationCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:AssetRetirementObligationCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:LossOnReacquiredDebtMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:DeferredLossOnEarlyExtinguishmentOfDebtMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:DeferredIncomeTaxChargesMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:PensionCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:PostretirementBenefitCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:AssetRecoverableGasCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:NaturalGasTransitionCostMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:RegulatoryClauseRevenuesUnderRecoveredMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:OtherRegulatoryAssetsLiabilitiesMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:RemovalCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:PensionAndOtherPostretirementPlansCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:DeferredDerivativeGainLossMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:RenewableEnergyProgramMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |
 | us-gaap:AdvancedMeteringInfrastructureCostsMember | domain-member | http://fasb.org/us-gaap/role/disclosure/RegulatedOperationsScheduleOfRegulatoryAssetsTable |