v2.4.0.6

Supplementary Information - Condensed Consolidating Financial Information - Additional Information (Detail) | Dec. 31, 2011
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ConocoPhillips Company [Member] |
Condensed Financial Statements, Captions [Line Items] |
Ownership percentage in subsidiaries | 100.00%
ConocoPhillips Australia Funding Company [Member] |
Condensed Financial Statements, Captions [Line Items] |
Ownership percentage in subsidiaries | 100.00%
ConocoPhillips Canada Funding Company I [Member] |
Condensed Financial Statements, Captions [Line Items] |
Ownership percentage in subsidiaries | 100.00%
ConocoPhillips Canada Funding Company II [Member] |
Condensed Financial Statements, Captions [Line Items] |
Ownership percentage in subsidiaries | 100.00%

X
- Definition The ownership percentage of the parent company to its subsidiary. + References No definition available. + Details
Name: | cop_PercentageOfOwnershipInterestHeldInSubsidiary
Namespace Prefix: | cop_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration