v2.4.0.6

Assets Held for Sale or Sold - Additional Information (Detail) (USD $) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009 | Dec. 31, 2011 Colonial Pipeline Colonial Ventures Seaway Crude Pipeline [Member] | Dec. 31, 2010 Syncrude Canada Ltd. [Member] | Jun. 30, 2010 Syncrude Canada Ltd. [Member] | Dec. 31, 2011 Vietnam E&P [Member]
Assets Held For Sale [Line Items] |  |  |  |  |  |  |
Net carrying value of asset |  |  |  | $ 348,000,000 |  | $ 1,750,000,000 |
Amount of investment in equity affiliates in carrying value of asset |  |  |  | 104,000,000 |  |  |
Amount of goodwill in carrying value of asset |  |  |  | 244,000,000 |  |  |
Gain on sale of asset |  |  |  | 1,661,000,000 | 2,900,000,000 |  |
Ownership interest in proportionally consolidated joint venture |  |  |  |  |  | 0.0903 |
Selling price of proportionally consolidated joint venture | 2,192,000,000 | 14,710,000,000 | 512,000,000 |  | 4,600,000,000 |  |
Amount of PP&E in carrying value of assets |  |  |  |  |  | 1,970,000,000 |
Expected proceeds from sale of assets |  |  |  |  |  |  | 1,290,000,000
Carrying value of assets to be sold |  |  |  |  |  |  | 150,000,000
PP&E in assets to be sold |  |  |  |  |  |  | $ 350,000,000

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

X
- 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). + References No definition available. + Details
Name: | cop_DisposalGroupIncludingDiscontinuedOperationAsSetOfDisposalGroup
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Expected proceeds from sale of asset. + References No definition available. + Details
Name: | cop_ExpectedProceedsFromSaleOfAsset
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Net carrying value of assets expected to be sold. + References No definition available. + Details
Name: | cop_NetCarryingValueOfAssetsExpectedToBeSold
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition P P and E in assets to be sold. + References No definition available. + Details
Name: | cop_PPAndEInAssetsToBeSold
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Cash inflows from disposals of property, plant and equipment (property dispositions) as well as net cash inflows associated with the sale of investments. + References No definition available. + Details
Name: | cop_ProceedsFromAssetDispositions
Namespace Prefix: | cop_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The percentage of ownership in a proportionally consolidated joint venture. + References No definition available. + Details
Name: | cop_ProportionallyConsolidatedJointVentureOwnershipPercentage
Namespace Prefix: | cop_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition For the disposal group, including a component of the entity (discontinued operation), carrying amount of goodwill (adjusted for any amortization recognized prior to adoption of FAS 142 and impairment charges). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 47 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For the disposal group, including a component of the entity (discontinued operation), carrying amount as of the balance sheet date of assets not otherwise specified, and which are expected to be realized or consumed after one year or beyond the normal operating cycle, if longer. For an unclassified balance sheet, represents both current and noncurrent other assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 47 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For the disposal group, including a component of the entity (discontinued operation), carrying value (net of accumulated depreciation and any write-downs) of tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 47 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Gain (loss) recorded from sale of oil and gas properties, includes the realized gains (losses) on the sale of proved and unproved oil and gas properties. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 19 -Paragraph 41, 44, 45, 46, 47 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_GainLossOnSaleOfOilAndGasProperty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration