2.3.0.11 Html 107 253 1 true 28 0 false 4 true false R1.htm 000990 - Document - Document And Entity Information Sheet http://questar.com/role/DocumentAndEntityInformation Document And Entity Information false false R2.htm 001000 - Statement - CONSOLIDATED STATEMENTS OF INCOME (Unaudited) Sheet http://questar.com/role/ConsolidatedStatementsOfIncomeUnaudited CONSOLIDATED STATEMENTS OF INCOME (Unaudited) false false R3.htm 002000 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) Sheet http://questar.com/role/CondensedConsolidatedBalanceSheetsUnaudited CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) false false R4.htm 003000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) Sheet http://questar.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) false false R5.htm 006010 - Disclosure - Nature of Business Sheet http://questar.com/role/NatureOfBusiness Nature of Business false false R6.htm 006020 - Disclosure - Basis of Presentation of Interim Financial Statements Sheet http://questar.com/role/BasisOfPresentationOfInterimFinancialStatements Basis of Presentation of Interim Financial Statements false false R7.htm 006030 - Disclosure - Comprehensive Income Sheet http://questar.com/role/ComprehensiveIncome Comprehensive Income false false R8.htm 006040 - Disclosure - Earnings Per Share Sheet http://questar.com/role/EarningsPerShare Earnings Per Share false false R9.htm 006050 - Disclosure - Asset Retirement Obligations Sheet http://questar.com/role/AssetRetirementObligations Asset Retirement Obligations false false R10.htm 006060 - Disclosure - Fair Value Measurements Sheet http://questar.com/role/FairValueMeasurements Fair Value Measurements false false R11.htm 006070 - Disclosure - Derivative Instruments and Hedging Activities Sheet http://questar.com/role/DerivativeInstrumentsAndHedgingActivities Derivative Instruments and Hedging Activities false false R12.htm 006080 - Disclosure - Share-Based Compensation Sheet http://questar.com/role/ShareBasedCompensation Share-Based Compensation false false R13.htm 006090 - Disclosure - Operations by Line of Business Sheet http://questar.com/role/OperationsByLineOfBusiness Operations by Line of Business false false R14.htm 006100 - Disclosure - Employee Benefits Sheet http://questar.com/role/EmployeeBenefits Employee Benefits false false R15.htm 006110 - Disclosure - Discontinued Operations Sheet http://questar.com/role/DiscontinuedOperations Discontinued Operations false false R16.htm 006120 - Disclosure - Recent Accounting Development Sheet http://questar.com/role/RecentAccountingDevelopment Recent Accounting Development false false R17.htm 006130 - Disclosure - Subsequent Event Sheet http://questar.com/role/SubsequentEvent Subsequent Event false false R18.htm 007020 - Disclosure - Basis of Presentation of Interim Financial Statements (Policies) Sheet http://questar.com/role/BasisOfPresentationOfInterimFinancialStatementsPolicies Basis of Presentation of Interim Financial Statements (Policies) false false R19.htm 008030 - Disclosure - Comprehensive Income (Tables) Sheet http://questar.com/role/ComprehensiveIncomeTables Comprehensive Income (Tables) false false R20.htm 008040 - Disclosure - Earnings Per Share (Tables) Sheet http://questar.com/role/EarningsPerShareTables Earnings Per Share (Tables) false false R21.htm 008050 - Disclosure - Asset Retirement Obligations (Tables) Sheet http://questar.com/role/AssetRetirementObligationsTables Asset Retirement Obligations (Tables) false false R22.htm 008060 - Disclosure - Fair Value Measurements (Tables) Sheet http://questar.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) false false R23.htm 008070 - Disclosure - Derivative Instruments and Hedging Activities (Tables) Sheet http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesTables Derivative Instruments and Hedging Activities (Tables) false false R24.htm 008080 - Disclosure - Share-Based Compensation (Tables) Sheet http://questar.com/role/ShareBasedCompensationTables Share-Based Compensation (Tables) false false R25.htm 008090 - Disclosure - Operations by Line of Business (Tables) Sheet http://questar.com/role/OperationsByLineOfBusinessTables Operations by Line of Business (Tables) false false R26.htm 008100 - Disclosure - Employee Benefits (Tables) Sheet http://questar.com/role/EmployeeBenefitsTables Employee Benefits (Tables) false false R27.htm 008110 - Disclosure - Discontinued Operations (Tables) Sheet http://questar.com/role/DiscontinuedOperationsTables Discontinued Operations (Tables) false false R28.htm 009010 - Disclosure - Nature of Business (Details) Sheet http://questar.com/role/NatureOfBusinessDetails Nature of Business (Details) false false R29.htm 009020 - Disclosure - Basis of Presentation of Interim Financial Statements (Details) Sheet http://questar.com/role/BasisOfPresentationOfInterimFinancialStatementsDetails Basis of Presentation of Interim Financial Statements (Details) false false R30.htm 009030 - Disclosure - Comprehensive Income (Details) Sheet http://questar.com/role/ComprehensiveIncomeDetails Comprehensive Income (Details) false false R31.htm 009040 - Disclosure - Earnings Per Share (Details) Sheet http://questar.com/role/EarningsPerShareDetails Earnings Per Share (Details) false false R32.htm 009050 - Disclosure - Asset Retirement Obligations (Details) Sheet http://questar.com/role/AssetRetirementObligationsDetails Asset Retirement Obligations (Details) false false R33.htm 009060 - Disclosure - Fair Value Measurements (Details) Sheet http://questar.com/role/FairValueMeasurementsDetails Fair Value Measurements (Details) false false R34.htm 009071 - Disclosure - Derivative Instruments and Hedging Activities, Narrative (Details) Sheet http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesNarrativeDetails Derivative Instruments and Hedging Activities, Narrative (Details) false false R35.htm 009072 - Disclosure - Derivative Instruments and Hedging Activities, Effects on Statements of Income and AOCI (Details) Sheet http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesEffectsOnStatementsOfIncomeAndAociDetails Derivative Instruments and Hedging Activities, Effects on Statements of Income and AOCI (Details) false false R36.htm 009073 - Disclosure - Derivative Instruments and Hedging Activities, Asset and Liability Derivative Instruments Designated as Hedges in the Balance Sheets (Details) Sheet http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesAssetAndLiabilityDerivativeInstrumentsDesignatedAsHedgesInBalanceSheetsDetails Derivative Instruments and Hedging Activities, Asset and Liability Derivative Instruments Designated as Hedges in the Balance Sheets (Details) false false R37.htm 009074 - Disclosure - Derivative Instruments and Hedging Activities, Additional Information (Details) Sheet http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesAdditionalInformationDetails Derivative Instruments and Hedging Activities, Additional Information (Details) false false R38.htm 009080 - Disclosure - Share-Based Compensation (Details) Sheet http://questar.com/role/ShareBasedCompensationDetails Share-Based Compensation (Details) false false R39.htm 009090 - Disclosure - Operations by Line of Business (Details) Sheet http://questar.com/role/OperationsByLineOfBusinessDetails Operations by Line of Business (Details) false false R40.htm 009100 - Disclosure - Employee Benefits (Details) Sheet http://questar.com/role/EmployeeBenefitsDetails Employee Benefits (Details) false false R41.htm 009110 - Disclosure - Discontinued Operations (Details) Sheet http://questar.com/role/DiscontinuedOperationsDetails Discontinued Operations (Details) false false R42.htm 009130 - Disclosure - Subsequent Event (Details) Sheet http://questar.com/role/SubsequentEventDetails Subsequent Event (Details) false false All Reports Book All Reports Element us-gaap_SeveranceCosts had a mix of decimals attribute values: -5 -6. Element us-gaap_GainLossOnDispositionOfAssets had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare had a mix of decimals attribute values: 2 0. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare had a mix of decimals attribute values: 2 0. Element us-gaap_CashAndCashEquivalentsAtCarryingValue had a mix of decimals attribute values: -5 -6. Element str_NotesReceivableFromParent had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeTaxReceivable had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax had a mix of decimals attribute values: -5 -6. Element str_AdvancesToUnconsolidatedAffiliate had a mix of decimals attribute values: -5 -6. Element us-gaap_ProceedsFromSaleOfProductiveAssets had a mix of decimals attribute values: -5 -6. Element us-gaap_PaymentsToAcquireNotesReceivable had a mix of decimals attribute values: -5 -6. Element us-gaap_ProceedsFromRepaymentsOfNotesPayable had a mix of decimals attribute values: -5 -6. Element us-gaap_PaymentsOfDebtIssuanceCosts had a mix of decimals attribute values: -5 -6. Element us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations had a mix of decimals attribute values: -5 -6. Element us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations had a mix of decimals attribute values: -5 -6. Element us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations had a mix of decimals attribute values: -5 -6. Element us-gaap_NetCashProvidedByUsedInDiscontinuedOperations had a mix of decimals attribute values: -5 -6. Element us-gaap_CashAndCashEquivalentsAtCarryingValue had a mix of decimals attribute values: -5 -6. Element us-gaap_CashAndCashEquivalentsAtCarryingValue had a mix of decimals attribute values: -5 -6. Element str_OtherComprehensiveIncomeEmployeeBenefitsAdjustmentBeforeTax had a mix of decimals attribute values: -5 -6. Element us-gaap_OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentBeforeTaxPeriodIncreaseDecrease had a mix of decimals attribute values: -5 -6. Element us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest had a mix of decimals attribute values: -5 -6. Element us-gaap_CashAndCashEquivalentsFairValueDisclosure had a mix of decimals attribute values: -5 -6. Element str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice had a mix of decimals attribute values: 2 0. Element us-gaap_DefinedBenefitPlanCurtailments had a mix of decimals attribute values: -5 -6. Element us-gaap_DefinedBenefitPlanSpecialTerminationBenefits had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity had a mix of decimals attribute values: -5 -6. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare had a mix of decimals attribute values: 2 0. Element us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare had a mix of decimals attribute values: 2 0. Process Flow-Through: 001000 - Statement - CONSOLIDATED STATEMENTS OF INCOME (Unaudited) Process Flow-Through: 002000 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) Process Flow-Through: Removing column 'Dec. 31, 2009' Process Flow-Through: 003000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) Process Flow-Through: Removing column '12 Months Ended Jun. 30, 2011' Process Flow-Through: Removing column '12 Months Ended Jun. 30, 2010' str-20110630.xml str-20110630.xsd str-20110630_cal.xml str-20110630_def.xml str-20110630_lab.xml str-20110630_pre.xml true true