Other Comprehensive Income Information (Schedule Of Accumulated Other Comprehensive Income Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Current period change excluding amounts reclassified from accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment	$ (2,337)	$ (1,367)	$ (3,546)	$ (322)
Amounts reclassified from accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment		(4,302)		(4,235)
Current period change excluding amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	454	1,236	898	1,629
Amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment	99	224	164	(180)
Beginning Balance, Total			(12,184)
Total change in accumulated other comprehensive income	(1,784)	(4,209)	(2,484)	(3,108)
Ending Balance, Total	(14,381)		(14,381)
Exxon Mobil Corporation Share After Noncontrolling Interest [Member]
Beginning Balance, Cumulative Foreign Exchange Translation Adjustment			2,410	4,168
Current period change excluding amounts reclassified from accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment			(3,214)	(266)
Amounts reclassified from accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment				(2,484)
Total change in accumulated other comprehensive income, Cumulative Foreign Exchange Translation Adjustment			(3,214)	(2,750)
Ending Balance, Cumulative Foreign Exchange Translation Adjustment	(804)	1,418	(804)	1,418
Beginning Balance, Postretirement Benefits Reserves Adjustment			(14,594)	(13,291)
Current period change excluding amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment			152	(152)
Amounts reclassified from accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment			865	1,366
Total change in accumulated other comprehensive income, Postretirement Benefits Reserves Adjustment			1,017	1,214
Ending Balance, Postretirement Benefits Reserves Adjustment	(13,577)	(12,077)	(13,577)	(12,077)
Beginning Balance, Total			(12,184)	(9,123)
Current period change excluding amounts reclassified from accumulated other comprehensive income, Total			(3,062)	(418)
Amounts reclassified from accumulated other comprehensive income, Total			865	(1,118)
Total change in accumulated other comprehensive income			(2,197)	(1,536)
Ending Balance, Total	$ (14,381)	$ (10,659)	$ (14,381)	$ (10,659)