Accounts payable and accrued liabilities current Accounts payable and accrued liabilities Total Total Income taxes payable Cumulative foreign exchange translation adjustment Ending Balance, Cumulative Foreign Exchange Translation Adjustment Beginning Balance, Cumulative Foreign Exchange Translation Adjustment Cumulative Translation adjustments Accumulated Other Comprehensive Income [Member] Exxon Mobil Share Of Accumulated Other Comprehensive Income [Member] Postretirement benefits reserves adjustment Postretirement benefits reserves adjustment Ending Balance, Postretirement Benefits Reserves Adjustment Beginning Balance, Postretirement Benefits Reserves Adjustment Ending Balance, Postretirement Benefits Reserves Adjustment Beginning Balance, Postretirement Benefits Reserves Adjustment Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax, Total Unrealized gain/(loss) on cash flow hedges Ending Balance, Unrealized Change in Fair Value on Cash Flow Hedges Beginning Balance, Unrealized Change in Fair Value on Cash Flow Hedges Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance, Total Beginning Balance, Total Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive income Adjustments to Additional Paid in Capital, Tax Effect from Share-based Compensation Tax benefits related to stock-based awards Current assets Assets Total assets Assets Of Disposal Group Including Discontinued Operation Total current assets Total current assets Total current assets Current assets Total assets Total assets Total assets Assets Held-for-sale, at Carrying Value Assets held for sale Assets Held-for-sale, at Carrying Value, Total Current assets Assets Of Disposal Group Including Discontinued Operation Current Basis Of Presentation Disclosure [Table Text Block] Basis Of Financial Statement Preparation Suspended exploratory well costs Charged to expense in period Cash and cash equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value, Total Increase/(decrease) in cash and cash equivalents Increase/(decrease) in cash and cash equivalents Commitments and contingencies Commitments and contingencies (Note 2) Common Stock [Member] Exxon Mobil Share Of Common Stock [Member] Common stock, without par value Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common stock, shares, outstanding Common stock without par value (9,000 million shares authorized, 8,019 million shares issued) Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common stock without par value: Authorized: 9,000 million shares; Issued: 8,019 million shares Common Stock, Value, Issued, Total Common stock, shares issued Common Stock, Shares, Issued, Total Common stock, shares authorized Dividends per common share (dollars) Dividends paid per common share (dollars) Other Comprehensive Income Information [Abstract] Comprehensive income attributable to ExxonMobil Comprehensive income attributable to ExxonMobil Comprehensive income attributable to ExxonMobil Comprehensive income attributable to noncontrolling interests Comprehensive income attributable to noncontrolling interests Comprehensive Income, Net of Tax, Attributable to Noncontrolling Interest, Total Comprehensive Income Note [Text Block] Summary of the change in accumulated other comprehensive income Other Comprehensive Income Information Comprehensive income including noncontrolling interests Net income including noncontrolling interests Comprehensive income including noncontrolling interests COSTS AND OTHER DEDUCTIONS Costs And Expenses Total costs and other deductions Total costs and other deductions Debt Instrument [Line Items] Recorded book values of total long-term debt including capitalized lease obligations Estimated fair value of total long-term debt, including capitalized lease obligations Total long-term debt Debt, Current, Total Notes and loans payable Total Short-term debt Deferred income tax liabilities Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Net pension enhancement and curtailment/settlement expense Net pension enhancement and curtailment/settlement cost Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements and Curtailments, Total Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlement and Curtailments Expected return on plan assets Expected return on plan assets Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Interest cost Interest cost Net benefit cost Net periodic benefit cost Net benefit cost Service cost Service cost Pension And Other Postretirement Benefits [Abstract] Defined Benefit Plans [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Depreciation and depletion Depreciation and depletion expense Segment Reporting Information, Depreciation, Depletion, and Amortization Expense, Total Discontinued Operations And Disposal Groups Abstract Net property, plant and equipment Disposal Group Including Discontinued Operation Property Plant And Equipment Net Other assets Disposal Group Including Discontinued Operation Other Noncurrent Assets Disposal Group Not Discontinued Operation Gain Loss On Disposal Gain associated with Japan Restructuring Disposal Groups Including Discontinued Operations Disclosure Text Block Disposal Groups Including Discontinued Operations Disclosure [Text Block] Other long-term obligations Disposal Group Including Discontinued Operation Other Noncurrent Liabilities Postretirement benefits reserves Disposal Group Including Discontinued Operation Pension Plan Benefit Obligation Dividends - common shares Dividends - common shares Dividends, Common Stock, Total Earnings per common share - assuming dilution (dollars) Earnings per common share - assuming dilution Earnings Per Share, Diluted, Total Earnings per common share (dollars) Earnings per common share Earnings Per Share, Basic, Total Earnings Per Share Text Block Earnings Per Share Earnings Per Share [Abstract] Effects of exchange rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents, Total Equity Component [Domain] Equity Component [Domain] Tax benefits related to stock-based awards Tax benefits related to stock-based awards Excess of Replacement or Current Costs over Stated LIFO Value Replacement cost of inventories estimated to exceed LIFO carrying values Aggregate replacement cost of inventories Sales and other operating revenue, sales-based taxes Sales-based taxes included in sales and other operating revenue Sales-based taxes Exploration expenses, including dry holes Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value Plan Asset Measurement [Domain] Fair Value Plan Asset Measurement [Domain] Fair Value Inputs Level3 [Member] Level 3 [Member] Fair Value Inputs Level1 [Member] Level 1 [Member] Fair Value Inputs Level2 [Member] Level 2 [Member] Foreign Pension Plans Defined Benefit [Member] Pension Benefits - Non-U.S. [Member] Guarantor Obligations by Nature [Axis] Guarantee Obligations Nature [Domain] Guarantor Obligations, Nature [Domain] Guarantees Total guarantees Guarantees, Total Income Including Equity Affiliate Earnings Before Income Taxes Income before income taxes Income before income taxes Total income before taxes Condensed Consolidated Statement Of Income [Abstract] Income from equity affiliates Income from equity affiliates Income from equity affiliates Income taxes Total income taxes Total income tax expense Total income tax expense Income taxes paid Cash payments for income taxes Income Taxes Paid, Net, Total Increase Decrease In Operating Capital Changes in operational working capital, excluding cash and debt Changes in operational working capital, excluding cash and debt Increase (Decrease) in Operating Capital, Total Changes in operational working capital, excluding cash and debt