2.2.0.25truefalse2000 - Disclosure - Cash Paid for Interest (Net of Amounts Capitalized) and Income Taxes, as well as Amounts Related to Non-Cash Transactions Table (Parenthetical) (Detail)truefalseIn Millionsfalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010 USD ($) / shares USD ($) $FROM_Jan01_2010_TO_Dec31_2010http://www.sec.gov/CIK0000773910duration2010-01-01T00:00:002010-12-31T00:00:00usdPerShrDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0MMboeStandardhttp://www.anadarko.com/20101231MMboeapc0USDUSD$2falsefalseUSDfalsefalse1/1/2009 - 12/31/2009 USD ($) USD ($) / shares $FROM_Jan01_2009_TO_Dec31_2009http://www.sec.gov/CIK0000773910duration2009-01-01T00:00:002009-12-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170usdPerShrDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0MMboeStandardhttp://www.anadarko.com/20101231MMboeapc0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$3falsefalseUSDfalsefalse1/1/2008 - 12/31/2008 USD ($) USD ($) / shares $FROM_Jan01_2008_TO_Dec31_2008http://www.sec.gov/CIK0000773910duration2008-01-01T00:00:002008-12-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0MMboeStandardhttp://www.anadarko.com/20101231MMboeapc0usdPerShrDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2false0us-gaap_IncomeTaxesPaidus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse308000000308falsetruefalsefalsefalse2truefalsefalse194000000194falsetruefalsefalsefalse3truefalsefalse10600000001060[1]falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 -Subparagraph f falsefalseIncome taxes3false0us-gaap_IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthorityus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3truefalsefalse567000000567falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.No authoritative reference available.falsefalseFederal income tax refund4false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.anadarko.com/role/disclosurecashpaidforinterestnetofamountscapitalizedandincometaxesaswellasamountsrelatedtononcashtransactionstableparentheticaldetail1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalseUSDtruefalse{us-gaap_ComponentOfOtherIncomeNonoperatingAxis} : Gain loss on disposition of assets [Member] 1/1/2008 - 12/31/2008 USD ($) $FROM_Jan01_2008_TO_Dec31_2008_us-gaap_ComponentOfOtherIncomeNonoperatingAxis_GainLossOnDispositionOfAssetsMemberhttp://www.sec.gov/CIK0000773910duration2008-01-01T00:00:002008-12-31T00:00:00falsefalseGain loss on disposition of assets [Member]us-gaap_ComponentOfOtherIncomeNonoperatingAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_GainLossOnDispositionOfAssetsMemberus-gaap_ComponentOfOtherIncomeNonoperatingAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalseGain loss on disposition of assets [Member]5false0us-gaap_IncomeTaxesPaidus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3truefalsefalse378000000378falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 -Subparagraph f falsefalseIncome taxes12008 includes $378 million and $567 million related to taxable gains on divestitures and federal income tax refunds, respectively.34Cash Paid for Interest (Net of Amounts Capitalized) and Income Taxes, as well as Amounts Related to Non-Cash Transactions Table (Parenthetical) (Detail) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue