2.2.0.25falsefalse40702 - Disclosure - Investments, Advances and Long-Term Receivables (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse12/31/2010
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$2falsefalseUSDfalsefalse12/31/2009
USD ($)
USD ($) / shares
$As_Of_12_31_2009http://www.sec.gov/CIK0000034088instant2009-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit14Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit13Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0us-gaap_LongTermInvestmentsAndReceivablesNetAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalse3false0us-gaap_EquityMethodInvestmentsus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1742900000017429falsetruefalsefalsefalse2truefalsefalse1574200000015742falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment losses recognized.No authoritative reference available.falsefalse4false0xom_AdvancesToEquityMethodCompaniesxomfalsedebitinstantAdvances To Equity Method Companiesfalsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse92860000009286falsefalsefalsefalsefalse2truefalsefalse86690000008669falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAdvances To Equity Method CompaniesNo authoritative reference available.falsefalse5false0xom_TotalInvestmentsAndAdvancesToEquityMethodCompaniesxomfalsedebitinstantTotal Investments And Advances To Equity Method Companiesfalsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse2671500000026715falsefalsefalsefalsefalse2truefalsefalse2441100000024411falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal Investments And Advances To Equity Method CompaniesNo authoritative reference available.truefalse6false0us-gaap_CostMethodInvestmentsus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse15570000001557falsefalsefalsefalsefalse2truefalsefalse15770000001577falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the aggregate carrying amount of all cost-method investments as reported on or included in the balance sheet. The original cost of the investments may differ from the aggregate carrying amount disclosed due to various adjustments such as: (i) dividends received in excess of earnings after the date of investment that are considered a return of investment and therefore recorded as reductions to cost of the investment, or (ii) a series of operating losses of an investee or other factors which may indicate that a decrease in value of the investment has occurred which is other than temporary and should accordingly be recognized.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 6
-Subparagraph a
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 03-1
-Paragraph 22
-Subparagraph a
Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 18
-Subparagraph a
falsefalse7false0us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVenturesus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse2827200000028272falsefalsefalsefalsefalse2truefalsefalse2598800000025988falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable form a party that is affiliated with the reporting entity by means of direct or indirect ownership.No authoritative reference available.truefalse8false0us-gaap_LongTermAccountsNotesAndLoansReceivableNetNoncurrentus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse70660000007066falsefalsefalsefalsefalse2truefalsefalse56770000005677falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate of amounts due from customers or clients more than one year from the balance sheet date, for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date more than one year from the balance sheet date, reduced to their estimated net realizable fair value by an allowance established by the Company of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 17
-Article 5
falsefalse9false0us-gaap_LongTermInvestmentsAndReceivablesNetus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse3533800000035338falsetruefalsefalsefalse2truefalsefalse3166500000031665falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle) and amount due to the Entity from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such investments and receivables to an amount that approximates their net realizable value.No authoritative reference available.truefalse28Investments, Advances and Long-Term Receivables (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
