 | us-gaap:DecommissioningTrustAssetsDescription | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DecommissioningTrustAssetsAmount | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:PlantHeldForFutureUseAmount | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:NuclearFuelNetOfAmortization | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:AdvancesForGasExplorationDevelopmentAndProductionAmount | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:UnrecoveredCostsForPurchasedGasAmount | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:ContributionsInAidOfConstruction | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DecommissioningLiabilityNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:SpentNuclearFuelObligationNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredFuelCost | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredStormAndPropertyReserveDeficiencyCurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DemandSideManagementProgramCostsNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:DeferredStormAndPropertyReserveDeficiencyNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:GasImbalancePayableCurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:GasImbalancePayableCurrentAndNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |
 | us-gaap:RefundableGasCosts | parent-child | http://fasb.org/us-gaap/role/disclosure/RegulatedOperations |