Consolidated Statement Of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidated Statement Of Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 33,615us-gaap_ProfitLoss	$ 33,448us-gaap_ProfitLoss	$ 47,681us-gaap_ProfitLoss
Other comprehensive income (net of income taxes)
Foreign exchange translation adjustment	(5,847)	(3,620)	920
Adjustment for foreign exchange translation (gain)/loss included in net income	152	(23)	(4,352)
Postretirement benefits reserves adjustment (excluding amortization)	(4,262)	3,174	(3,574)
Amortization and settlement of postretirement benefits reserves adjustment included in net periodic benefit costs	1,111	1,820	2,395
Unrealized change in fair value of stock investments	(63)
Realized (gain)/ loss from stock investments included in net income	3
Total other comprehensive income	(8,906)	1,351	(4,611)
Comprehensive income including noncontrolling interests	24,709	34,799	43,070
Comprehensive income attributable to noncontrolling interests	421	760	1,251
Comprehensive income attributable to ExxonMobil	$ 24,288us-gaap_ComprehensiveIncomeNetOfTax	$ 34,039us-gaap_ComprehensiveIncomeNetOfTax	$ 41,819us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax, before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for translation gain (loss) realized upon the sale or liquidation of an investment in a foreign entity and foreign currency hedges that are designated and qualified as hedging instruments for hedges of the foreign currency exposure of a net investment in a foreign operation.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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The adjustment out of other comprehensive income for prior service costs, actuarial gains and losses and other previously recorded other comprehensive income recognized as a component of net period benefit cost during the period, after tax.

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