<DefinitionAndReference>
  <Element Id="us-gaap_Assets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SummaryLineItemsAffectedOnStatementOfCashFlowsTextBlock">
    <definition>Summary Line Items Affected on Consolidated Statement of Cash Flows .</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NotionalAmountOfForeignCurrencyDerivativePurchaseContracts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentsUnderLongTermThroughputAgreementsAndTakeOrPayAgreementsDueInThirdYear">
    <definition>Payments Under Long Term Throughput Agreements And Take Or Pay Agreements Due In Third Year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ExcessOfReplacementOrCurrentCostsOverStatedLIFOValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TotalPeriodOfAmortizationOfBasisDifferenceInYears">
    <definition>Total period of amortization of basis difference, in years.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromPaymentsForOtherFinancingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_InitialAcquisitionObligationToJointVenture">
    <definition>Obligation to Joint Venture over a 10-year period, beginning in 2007.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_EffectiveYieldRate">
    <definition>Effective yield rate.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxesPaidNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_EquityMethodInvestmentNumberOfSharesSold">
    <definition>Equity Method Investment Number Of Shares Sold.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SegmentReportingInformationTotalAssetsBySegmentTextBlock">
    <definition>Segment Reporting Information Total Assets By Segment Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FixedAnnualInterestRateOnJointVentureAcquisitionObligation">
    <definition>Fixed annual interest rate used to accrue interest on unpaid principal balance of Joint Venture Acquisition Obligation</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromIssuanceOfCommonStock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PricePerShareForSellingRemainingSharesUnder60DayOptionGrantedUnderAgreement">
    <definition>Price Per Share For Selling Remaining Shares Under 60 Day Option Granted Under Agreement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CondensedConsolidatedBalanceSheetTextBlock">
    <definition>Condensed Consolidated Balance Sheet.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ReceivablesNetCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdditionalCollateralAggregateFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SalesConsiderationOfInvestmentsUnderAgreement">
    <definition>Sales consideration of investments under agreement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleAmountOfImpairmentLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AssetImpairmentCharges">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DueFromRelatedPartiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentTermOfRecievables">
    <definition>Payment term of recievables.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_TreasuryStockShares">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SyncrudePortionOfSalesAndOtherOperatingRevenueThroughDispositonDate">
    <definition>For a disposal group that is a component of the entity (discontinued operation), in the period in which the operations are initially classified as discontinued, the amounts of intercompany revenue that were previously eliminated in consolidation for periods before the disposal transaction (in situations where revenue and cost producing activities with the disposed component will continue after disposal).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PricePerShareForSellingSharesUnderAgreement">
    <definition>Price per share for selling shares under agreement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_EmployeeBenefitObligationsNoncurrent">
    <definition>For classified balance sheets this represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit plans.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PercentageOfFundingObligationForTerminalExpansionLoan">
    <definition>Obligation to fund, through loans, for terminal's expansion costs.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CommercialPaperProgramInternationalProject">
    <definition>Commercial Paper Program, International Project.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_OwnershipInterestOfOthersInVie">
    <definition>Ownership interest of others in a VIE.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisDerivativeFinancialInstrumentsLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInReceivables">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DepreciationDepletionAndAmortization">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ProceedsFromAssetDispositions">
    <definition>Cash inflows from disposals of property, plant and equipment (property dispositions) as well as net cash inflows associated with the sale of investments.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TermsToDeliverNaturalGasUnderSalesAgreementsMaximum">
    <definition>Terms to deliver natural gas under sales agreements maximum.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TerminalsGrossOilThroughputCapacityInBarrelsPerDayAfterExpansion">
    <definition>Terminal's gross oil-throughput capacity in barrels per day after expansion.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentNetSalesProceeds">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CapacityOfMereySweenyLimitedPartnershipFacilityBarrelsPerDay">
    <definition>Capacity of Mery Sweeny Limited Partnership facility, barrels-per-day.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherLiabilitiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccrualForEnvironmentalLossContingenciesNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnearnedESOPShares">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsForProceedsFromOtherInvestingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FinancialAssets">
    <definition>Assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements, and net of obligations ot return cash collateral.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_GainsLossesFromCommodityDerivativesTextBlock">
    <definition>Gains losses from commodity derivatives Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss">
    <definition>This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets) in sales and other operating revenues. Such unrealized (holding) gains or losses relate to those liabilities still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_MinorityInterestDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_GainsLossesFromForeignCurrencyDerivativesTextBlock">
    <definition>Gains Losses From Foreign Currency Derivatives TextBlock.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesOther">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentsUnderLongTermThroughputAgreementsAndTakeOrPayAgreementsDueWithinOneYear">
    <definition>Payments Under Long Term Throughput Agreements And Take Or Pay Agreements Due within One Year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityPublicFloat">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_LoanFacilitiesOfJointVenture">
    <definition>Loan facilities of joint venture.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentPeriodEndDate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityCentralIndexKey">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueAssetsMeasuredOnRecurringBasisDerivativeFinancialInstrumentsAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_DetailsOfImpairmentOfLongLivedAssetsTextBlock">
    <definition>For long-lived assets, disclosures may include a description of the impaired long-lived asset and facts and circumstances leading to the impairment, amount of the impairment loss and where the loss is located in the income statement, method(s) for determining fair value, and the segment in which the impaired long-lived asset is reported.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_LongTermAgreementToUseRegasificationCapacityCubicFeetPerDay">
    <definition>Long-term agreement with Freeport LNG to use LNG regasification capacity, cubic feet per day.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GainLossOnSaleOfOilAndGasProperty">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AssetsHeldForSaleAtCarryingValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_OtherCommonStockholdersEquity">
    <definition>Other common stockholders' equity, excluding retained earnings and noncontrolling interest.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_GainsLossesFromInterestRateDerivativesUsedInFairValueHedgeAsWellAsLossesGainsFromChangesInFairValueOfHedgedDebtTextBlock">
    <definition>(Gains) losses from interest rate derivatives used in a fair value hedge, as well as losses (gains) from changes in fair value of hedged debt Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ImpairmentOfLongLivedAssetsHeldForUse">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_UnusedLettersOfCredit">
    <definition>Unused letters of credit.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ApproximateOwnershipLevelAtWhichEquityMethodAccountingWouldLikelyBeDiscontinued">
    <definition>Approximate ownership level at which equity method accounting would likely be discontinued.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_TaxesPayableCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityCurrentReportingStatus">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EarningsPerShareDiluted">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CashFlowInformationDisclosureTextBlock">
    <definition>Cash Flow Information.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockholdersEquity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockIssuedEmployeeTrustDeferred">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_JointVentureAcquisitionOblilgationQuarterlyPayment">
    <definition>Amount of the required quarterly payments including both interest and principal payments for Joint Venture Acquisition Obligation.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccountsPayableCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ImpairmentChargesBySegmentBeforeTaxTextBlock">
    <definition>Impairment charges by segment before tax.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LiabilitiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AmountConvertedByInterestRateSwapExecution">
    <definition>Amount converted by interest rate swap execution.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CommittedAmountOfConstructionLoan">
    <definition>Committed Amount Of Construction Loan.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityFilerCategory">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SegmentReportingInformationSalesAndOtherOperatingRevenueByBusinessSegmentTextBlock">
    <definition>Segment Reporting Information Sales and Other Operating Revenue by Business Segment.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherLiabilitiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetIncomeLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfVariableInterestEntitiesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GuaranteeObligationsMaximumExposure">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RelatedPartyTransactionRevenuesFromTransactionsWithRelatedParty">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentsUnderLongTermThroughputAgreementsAndTakeOrPayAgreementsDueInSecondYear">
    <definition>Payments Under Long Term Throughput Agreements And Take Or Pay Agreements Due In Second Year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_TreasuryStockValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NonsponsoredPlans">
    <definition>Net changes in other comprehensive income related to benefit plans, after tax, attributable to the Company's proportionate share of equity investees' interest.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueOfInterestRateDerivativeContractsWithoutNettingTextBlock">
    <definition>Fair value of interest rate derivative contracts, without netting Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CostOfPurchasedOilAndGas">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SalesPriceOfProportionallyConsolidatedJointVenture">
    <definition>Sales price of a proportionally consolidated joint venture.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PropertyPlantAndEquipmentGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_RepaymentOfDebt">
    <definition>The cash outflow due to total repayments of additional borrowing.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss">
    <definition>This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets) in sales and other operating revenues. Such unrealized (holding) gains or losses relate to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CapitalExpendituresAndInvestments">
    <definition>Cash outflows for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets as well as net cash outflows associated with the acquisition of investments.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockSharesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SellingGeneralAndAdministrativeExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_OtherChangesNet">
    <definition>Other changes, net.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherInventorySupplies">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueOfForeignCurrencyDerivativeAssetsAndLiabilitiesWithoutNettingTextBlock">
    <definition>Fair Value Of Foreign Currency Derivative Assets And Liabilities Without Netting TextBlock.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NumberOfSharesToBeSoldUnderAgreement">
    <definition>Number of shares to be sold under agreement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtInstrumentInterestRateStatedPercentage">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TerminalsGrossOilThroughputCapacityInBarrelsPerDayBeforeExpansion">
    <definition>Terminals Gross Oil Throughput Capacity In Barrels Per Day Before Expansion.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOut">
    <definition>This element represents transfers out of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueOfNetCommodityDerivativesClassifiedAsLevel3TextBlock">
    <definition>Fair Value Of Net Commodity Derivatives Classified As Level 3 Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ExpectedYearsToIncurMajorityOfExpenditures">
    <definition>Expected years to incur the majority of expenditures.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TermsOfGuaranteesOutstanding">
    <definition>Terms of guarantees outstanding.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentFiscalYearFocus">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetCashProvidedByUsedInOperatingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LIFOInventoryAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ClosingPricePerShareOnLondonStockExchange">
    <definition>Closing Price Per Share On The London Stock Exchange.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_Goodwill">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FinancialLiabilities">
    <definition>Liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements, and net of rights to reclaim cash collateral.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInInventories">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_RelatedPartyTransactionsTextBlock">
    <definition>Related Party Transactions.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ScheduleOfComponentsOfNetPeriodicBenefitCostsTextBlock">
    <definition>This element may be used to capture the entire disclosure for an employer that sponsors one or more defined benefit pension plans or one or more other defined benefit postretirement plans, of certain information, separately for pension plans and other postretirement benefit plans, including the entity's schedule of fair value of plan assets for defined benefit or other postretirement plans.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_GrantorTrustShares">
    <definition>Number of shares of common stock held in a trust that has been set up specifically to accumulate stock for the sole purpose of distribution to participating employees, but not yet earned.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AccountsPayableExcludingRelatedParties">
    <definition>Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. For classified balance sheets, used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer); for unclassified balance sheets, used to reflect the total liabilities (regardless of due date). Also excludes Accounts-payable related parties, which is presented on a separate line item.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NetExposuresFromOutstandingCommodityDerivativeContractsTextBlock">
    <definition>Net exposures from outstanding commodity derivative contracts Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ExplorationExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AccumulatedOtherComprehensiveIncomeLossTextBlock">
    <definition>Accumulated other comprehensive income loss in the equity section.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdditionalPaidInCapitalCommonStock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InterestRateFairValueHedgeAssetAtFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SummaryLineItemsAffectedOnIncomeStatementTextBlock">
    <definition>Summary Line Items Affected On Consolidated Income Statement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LiabilitiesAndStockholdersEquity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ExplorationAbandonmentAndImpairmentExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_RightsToReclaimCashCollateral">
    <definition>Rights to reclaim cash collateral.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanActuarialNetGainsLosses">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockParOrStatedValuePerShare">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PercentOfQuarterlyInterestPaymentAsCapitalContribution">
    <definition>Percent of the quarterly interest payment that is reflected as a capital contribution.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AmountsOfLevel3GainsLossesTextBlock">
    <definition>Amounts of Level 3 gains losses Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfGuaranteeObligationsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInAccountsPayable">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_JointVentureAcquisitionObligationTextBlock">
    <definition>Long-term funding commitments to joint ventures or other affiliates.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_CurrentFiscalYearEndDate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_RelatedPartyTransactionPurchasesFromRelatedParties">
    <definition>Purchase costs resulting from transactions with related parties during the period.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsOfDividendsCommonStock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FinancialInstrumentsAndDerivativeContractsTextBlock">
    <definition>This item represents the complete disclosure regarding the fair value of financial instruments, including financial assets and financial liablities, and the measurements of those instruments, as well as the entity's entire derivative instruments and hedging activities disclosure as a single block of text.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AverageOwnershipInterestInFirstQuarter2010">
    <definition>Average ownership interest in first quarter 2010.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GainLossOnSaleOfOtherAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_LettersOfCreditIssuedUnderRevolvingCreditFacilities">
    <definition>Letters of credit issued under revolving credit facilities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RepaymentsOfLongTermDebt">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentsUnderLongTermThroughputAgreementsAndTakeOrPayAgreementsDueInFifthYear">
    <definition>Payments Under Long Term Throughput Agreements And Take Or Pay Agreements Due In Fifth Year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_VariableInterestEntityOwnershipPercentage">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProfitLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InterestAndDebtExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_IntercompanyRevenues">
    <definition>Intercompany revenues.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ShortTermPortionOfPrincipalObligationAmount">
    <definition>Short term portion of principal obligation amount.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CommodityDerivativeOfAssetsAndLiabilitiesTextBlock">
    <definition>Commodity derivative of assets and liabilities Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FixedRateOnJointVentureAcquisitionObligation">
    <definition>Fixed-rate on joint venture acquisition obligation.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashAndCashEquivalentsAtCarryingValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxLiabilitiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NetPriorServiceCost">
    <definition>The cost of benefit improvement resulting from a plan amendment that occurred during the period, after tax. The cost has not been recognized in net periodic benefit cost pursuant to FAS 87 and 106. A plan amendment includes provisions that grant increased benefits based on services rendered in prior periods. This also includes the adjustment out of other comprehensive income for prior service costs recognized as a component of net period benefit cost during the period, after tax.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_InvestmentsAndLongTermReceivables">
    <definition>Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Also includes the aggregate of amounts due from customers or clients more than one year from the balance sheet date, for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date more than one year from the balance sheet date, reduced to their estimated net realizable fair value by an allowance established by the Company of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively. Excludes Related party loans and advances that are shown on a separate line.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_AmendmentFlag">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_Liabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_GuarantorObligationsMaximumExposureUndiscountedRecklessBreach">
    <definition>Maximum Potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries, under recourse or collateralization provisions, in the event of intentional or reckless breach.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TotalRevenuesAndOtherIncome">
    <definition>Aggregate revenue recognized during the period, including Other Income and Equity in Earnings of Affiliates.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SegmentReportingDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentsUnderLongTermThroughputAgreementsAndTakeOrPayAgreementsDueAfterFifthYear">
    <definition>Payments Under Long Term Throughput Agreements And Take Or Pay Agreements Due After Fifth Year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockSharesAuthorized">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AssetRetirementObligationsAndAccruedEnvironmentalCosts">
    <definition>Non current portion of the carrying amount of a liability for an asset retirement obligation, as well as the carrying value of an obligation (known or estimated) arising from requirements to perform activities to remediate one of more sites, payable after twelve months or beyond the next operating cycle if longer.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ChangeInEquityAttributableToNoncontrollingInterestsTextBlock">
    <definition>Change in equity attributable to noncontrolling interests.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PaymentsUnderLongTermThroughputAgreementsAndTakeOrPayAgreementsDueInFourthYear">
    <definition>Payments Under Long Term Throughput Agreements And Take Or Pay Agreements Due In Fourth Year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_InvestmentsAndLongTermReceivablesIncludingLoansAndAdvancesRelatedParties">
    <definition>Investments and long-term receivables including Loans and advances-related parties.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NotionalAmountOfForeignCurrencyDerivativeSaleContracts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ScheduleOfInventoriesDisclosureTextBlock">
    <definition>Schedule of Inventories Disclosure.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InventoryCrudeOilProductsAndMerchandise">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NetInterestExpenseRelatedParty">
    <definition>Interest paid to or received from various related parties.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateContinuingOperations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InvestmentOwnedBalanceShares">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_DisposalGroupIncludingDiscontinuedOperationAssetOfDisposalGroup">
    <definition>Description, in aggregate or in detail, of the major classifications and carrying amounts of total assets sold, or to be sold, as part of the disposal group, including a component of the entity (discontinued operation).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_MaturityPeriodOfDebtInstrument">
    <definition>Maturity period of Debt Instrument.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TotalCostsAndExpenses">
    <definition>Total costs and expenses, including operating expenses and non-operating expenses.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PrepaidExpensesAndOtherCurrentAssets">
    <definition>Sum of the amounts paid in advance for capitalized costs that will be expensed with the passage of time or the occurrence of a triggering event, and will be charged against earnings within one year or the normal operating cycle, if longer. Also included is the aggregate carrying amount, as of the balance sheet date, of current assets not separately disclosed in the balance sheet due to materiality considerations. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer.)</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentFiscalPeriodFocus">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanContributionsByEmployer">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ComprehensiveIncomeNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InventoryDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CommercialPaperProgram">
    <definition>Commercial Paper Program.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsForRepurchaseOfCommonStock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeLossFromEquityMethodInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DueFromRelatedPartiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_IssuanceOfDebt">
    <definition>The cash inflow due to total proceeds from additional borrowings.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PropertyPlantAndEquipmentNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SalesRevenueNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeFairValueOfDerivativeLiability">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SegmentReportingInformationNetIncomeLossAttributableToParentTextBlock">
    <definition>Segment Reporting Information Net Income Loss Attributable To Parent Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentType">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DueFromRelatedParties">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_LoanBalanceOutstandingToVie">
    <definition>Loan balance outstanding to VIE.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NumberOfProductionBarrelsPerDay">
    <definition>Number of production barrels per day.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashFlowSupplementalDisclosuresTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AssetsCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RelatedPartyTransactionsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AdditionalEquityMethodOwnershipInterestAcquiredInMereySweenyLimitedPartnership">
    <definition>Additional equity method ownership interest acquired in Merey Sweeny Limited Partnership from Petroleos De Venezuela S.A. (PDVSA).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxExpenseBenefit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NetPositionOfOutstandingForeignCurrencySwapContractsTextBlock">
    <definition>Net position of outstanding foreign currency swap contracts.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisValuationTechniquesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SummaryLineItemsAffectedOnBalanceSheetTextBlock">
    <definition>Summary Line Items Affected on Consolidated Balance Sheet.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_EmployeeBenefitObligationsCurrent">
    <definition>Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses. For classified balance sheets, used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer); for unclassified balance sheets, used to reflect the total liabilities (regardless of due date).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InventoryNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeFairValueOfDerivativeAsset">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="invest_DerivativeNonmonetaryNotionalAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IntangibleAssetsNetExcludingGoodwill">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ProportionallyConsolidatedJointVentureOwnershipPercentage">
    <definition>The percentage of ownership in a proportionally consolidated joint venture.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_IncreaseDecreaseInTaxesAndOtherAccruals">
    <definition>Net change during the reporting period in current income taxes, other accruals payable and other expenses incurred but not yet paid. This element includes items where no more specific or appropriate element exists.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanServiceCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherNonoperatingIncome">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TermsToDeliverNaturalGasUnderSalesAgreementsMinimum">
    <definition>Terms to deliver natural gas under sales agreements minimum.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ProductionAndOperatingExpenses">
    <definition>Generally recurring costs associated with normal operations, excluding DD&amp;A; Selling, General and Administrative Expense; Accretion; and Exploration Expense.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetCashProvidedByUsedInFinancingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherAssetsNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentQuotedMarketValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_IncomeLossBeforeIncomeTaxes">
    <definition>Sum of operating profit and nonoperating income (expense) before income taxes and minority interest, and including equity in earnings of affiliates.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_MinorityInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalizedExploratoryWellCostPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanInterestCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SyncrudePortionOfNetIncomeThroughDispositonDate">
    <definition>After tax income (loss) from operations of a business component (exclusive of any gain or loss on disposal, or provision therefore) during the reporting period, until its disposal.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_IrrevocableEarlyRedemptionNoticesIssued">
    <definition>Irrevocable early redemption notices issued.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_NetActuarialGain">
    <definition>The accumulated change in the value of either the projected benefit obligation or the plans assets resulting from experience different from that assumed or from a change in an actuarial assumption that has not been recognized in net periodic benefit cost pursuant to FAS 87 and 106, after tax. This also includes the adjustment out of other comprehensive income for actuarial gains (losses) recognized as a component of net periodic benefit cost during the period, after tax.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockDividendsPerShareCashPaid">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermDebtAndCapitalLeaseObligations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetCashProvidedByUsedInInvestingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FairValueMeasuredOnRecurringBasisInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ObligationsToReturnCashCollateral">
    <definition>Obligations to return cash collateral.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityRegistrantName">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ComprehensiveIncomeTextBlock">
    <definition>Comprehensive income.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevelThree">
    <definition>This element represents transfers into assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InterestPaidNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShortTermInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SyntheticOilProvedReservesInExplorationAndProductionSegment">
    <definition>Synthetic oil proved reserves in exploration and production segment.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_SyncrudePortionOfIncomeBeforeIncomeTaxesThroughDispositonDate">
    <definition>Pretax income (loss) from operations of a business component (exclusive of any gain or loss on disposal, or provision therefore) during the reporting period, until its disposal.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AccretionOnDiscountedLiabilities">
    <definition>Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present value, including accretion associated with asset retirement obligations, decommissioning, environmental, and other contingencies.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_TaxesOtherThanIncomeTaxes">
    <definition>Taxes other than income taxes, if not included elsewhere, that could include, payroll tax, property tax or other selling and distribution-related taxes. Also includes excise taxes.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GuaranteeObligationsCurrentCarryingValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_ReclassificationOfShortTermDebtAsLongTermDebt">
    <definition>Reclassification of short term debt as long term debt.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsForAdvanceToAffiliate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CommodityDerivativeAndFinancialInstrumentsTextBlock">
    <definition>Commodity derivative and financial instruments Text Block.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DueToRelatedPartiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CondensedConsolidatedIncomeStatementTextBlock">
    <definition>Condensed Consolidated Income Statement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_MaturityPeriodOfCommercialPaper">
    <definition>Maturity period of commercial paper.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentOwnershipPercentage">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AcccruedInterestOnFinancing">
    <definition>Accrued interest on financing.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_JointVentureAcquisitionObligationPrincipalPayment">
    <definition>Amount of the required quarterly payments applied to principal.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityWellKnownSeasonedIssuer">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RetainedEarningsAccumulatedDeficit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityVoluntaryFilers">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ComprehensiveIncomeNoteTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommercialPaper">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_CondensedConsolidatedCashFlowsTextBlock">
    <definition>Condensed Consolidated Cash Flows.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_PropertiesPlantsAndEquipmentTextBlock">
    <definition>Properties Plants And Equipment.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredIncomeTaxExpenseBenefit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="cop_AccountsAndNotesReceivableNetOfAllowance">
    <definition>The aggregate of amounts due from customers or clients, within one year of the balance sheet date (or one operating cycle, if longer), for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date within one year of the balance sheet, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively. Also excludes related party receivables.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EarningsPerShareBasic">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityCommonStockSharesOutstanding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DueToRelatedPartiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalizedExploratoryWellCosts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
</DefinitionAndReference>
