Other Comprehensive Income Information (Schedule Of Accumulated Other Comprehensive Income Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Period Increase Decrease [Abstract]
Current period change excluding amounts reclassified from accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment	$ 741	$ 149
Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Period Increase Decrease [Abstract]
Current period change excluding amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	105	168
Amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	93	378
Other Comprehensive Income Loss Net Of Tax Period Change [Abstract]
Beginning Balance, Total	(13,764)
Ending Balance, Total	(12,914)
Exxon Mobil Corporation Share After Noncontrolling Interest [Member]
Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Period Increase Decrease [Abstract]
Beginning Balance, Cumulative Foreign Exchange Translation Adjustment	(11,499)	(10,614)
Current period change excluding amounts reclassified from accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment	661	88
Adjustment for foreign exchange translation (gain)/loss included in net income	0	0
Total change in accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment	661	88
Ending Balance, Cumulative Foreign Exchange Translation Adjustment	(10,838)	(10,526)
Net investment hedge gain/(loss), net of taxes	79	191
Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Period Increase Decrease [Abstract]
Beginning Balance, Postretirement Benefits Reserves Adjustment	(2,265)	(6,091)
Current period change excluding amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	102	158
Amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	87	369
Total change in accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	189	527
Ending Balance, Postretirement Benefits Reserves Adjustment	(2,076)	(5,564)
Other Comprehensive Income Loss Net Of Tax Period Change [Abstract]
Beginning Balance, Total	(13,764)	(16,705)
Current period change excluding amounts reclassified from accumulated other comprehensive income, Total	763	246
Amounts reclassified from accumulated other comprehensive income, Total	87	369
Total change in accumulated other comprehensive income, Total	850	615
Ending Balance, Total	$ (12,914)	$ (16,090)