2.2.0.25truefalse41501 - Disclosure - Litigation and Other Contingencies (Narrative) (Details)truefalseIn Millions, unless otherwise specifiedfalse1falsefalseUSDfalsefalse12/31/2010
USD ($)
USD ($) / shares
$As_Of_12_31_2010http://www.sec.gov/CIK0000034088instant2010-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit13Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit14Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2falsefalsefalsefalse5/1/2007
As_Of_5_1_2007http://www.sec.gov/CIK0000034088instant2007-05-01T00:00:000001-01-01T00:00:00Unit14Standardhttp://www.xbrl.org/2003/instancepurexbrli03falsefalseUSDtruefalse{us-gaap_LossContingenciesByNatureOfContingencyAxis} : Equity Company Obligations [Member]
12/31/2010
USD ($)
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12/31/2010
USD ($)
$As_Of_12_31_2010845http://www.sec.gov/CIK0000034088instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseGuarantees, Notes, Loans And Performance [Member]us-gaap_LossContingenciesByNatureOfContingencyAxisxbrldihttp://xbrl.org/2006/xbrldixom_GuaranteesForNotesLoansAndPerformanceMemberus-gaap_LossContingenciesByNatureOfContingencyAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5falsefalsetruefalse{us-gaap_LossContingenciesByNatureOfContingencyAxis} : Expropriation of Assets [Member]
6/27/2007
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph c
falsefalse3false0xom_PercentageOwnershipInterestOfOverseasProjectBeforeNationalizationDecreeByForeignNationxomfalsenainstantPercentage Ownership Interest Of Overseas Project Before Nationalization Decree By Foreign Nationfalsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsetruefalse00falsefalsefalsefalsefalse2truetruefalse0.41670.4167falsefalsefalsefalsefalse3falsetruefalse00falsefalsefalsetruefalse4falsetruefalse00falsefalsefalsetruefalse5truetruefalse0.41670.4167falsefalsefalsetruefalseOtherus-types:percentItemTypepurePercentage Ownership Interest Of Overseas Project Before Nationalization Decree By Foreign NationNo authoritative reference available.falsefalse4false0us-gaap_InvestmentsInAndAdvancesToAffiliatesBalancePrincipalAmountus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse750000000750falsetruefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFor investments which are quantified by principal amount, the principle balance held at close of period.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 14
-Paragraph Column B
-Article 12
falsefalse53Litigation and Other Contingencies (Narrative) (Details) (USD $)MillionsUnKnownUnKnownUnKnowntruetrue
