v2.4.0.6

Joint Venture Acquisition Obligation (Details) (USD $) | 9 Months Ended
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Sep. 30, 2012
Joint Venture Acquisition Obligation (Textual) [Abstract] |
Initial acquisition obligation to joint venture | $ 7,500,000,000
Time period for contribution | 10
Quarterly principal and interest payments for joint venture acquisition obligation | 237,000,000
Short-term portion of principal obligation amount | 763,000,000
Principal payment for joint venture obligation | $ 546,000,000
Percentage of quarterly interest payment as capital contribution | 50.00%

X
- Definition Obligation to Joint Venture over a 10-year period, beginning in 2007. + References No definition available. + Details
Name: | cop_InitialAcquisitionObligationToJointVenture
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of the required quarterly payments applied to principal. + References No definition available. + Details
Name: | cop_JointVentureAcquisitionObligationPrincipalPayment
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the required quarterly payments including both interest and principal payments for Joint Venture Acquisition Obligation. + References No definition available. + Details
Name: | cop_JointVentureAcquisitionObligationQuarterlyPayment
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | cop_JointVentureAcquisitionObligationTextualAbstract
Namespace Prefix: | cop_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent of the quarterly interest payment that is reflected as a capital contribution. + References No definition available. + Details
Name: | cop_PercentOfQuarterlyInterestPaymentAsCapitalContribution
Namespace Prefix: | cop_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Short-term portion of principal obligation amount. + References No definition available. + Details
Name: | cop_ShortTermPortionOfPrincipalObligationAmount
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Time period for contribution. + References No definition available. + Details
Name: | cop_TimePeriodForContribution
Namespace Prefix: | cop_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration