Condensed Consolidating Financial Information Related to Guaranteed Securities Issued by Subsidiaries (Schedule of Condensed Consolidated Statement of Cash Flows) (Details) (USD $) In Millions	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash provided by/(used in) operating activities	$ 29,745	$ 22,281
Additions to property, plant and equipment	(14,863)	(11,400)
Sales of long-term assets	2,838	852
Net intercompany investing
All other investing, net	(3,832)	303
Net cash provided by/(used in) investing activities	(15,857)	(10,245)
Additions to long-term debt	249	33
Reductions in long-term debt	(43)	(16)
Additions/(reductions) in short-term debt - net	1,182	(697)
Cash dividends to ExxonMobil shareholders	(4,496)	(4,052)
Net ExxonMobil shares sold/(acquired)	(10,713)	(3,952)
Net intercompany financing activity
All other financing, net	7	(113)
Net cash provided by/(used in) financing activities	(13,814)	(8,797)
Effects of exchange rate changes on cash	388	(680)
Increase/(decrease) in cash and cash equivalents	462	2,559
ExxonMobil Corporation Parent Guarantor [Member]
Cash provided by/(used in) operating activities	3,739	30,671
Additions to property, plant and equipment	(1,337)	(1,234)
Sales of long-term assets	163	319
Net intercompany investing	13,258	(21,586)
All other investing, net	(1,323)
Net cash provided by/(used in) investing activities	10,761	(22,501)
Additions to long-term debt
Reductions in long-term debt
Additions/(reductions) in short-term debt - net	873	(40)
Cash dividends to ExxonMobil shareholders	(4,496)	(4,052)
Net ExxonMobil shares sold/(acquired)	(10,713)	(3,952)
Net intercompany financing activity
All other financing, net	171	28
Net cash provided by/(used in) financing activities	(14,165)	(8,016)
Effects of exchange rate changes on cash
Increase/(decrease) in cash and cash equivalents	335	154
SeaRiver Maritime Financial Holdings Inc [Member]
Cash provided by/(used in) operating activities	2	1
Additions to property, plant and equipment
Sales of long-term assets
Net intercompany investing	(177)	(151)
All other investing, net
Net cash provided by/(used in) investing activities	(177)	(151)
Additions to long-term debt
Reductions in long-term debt
Additions/(reductions) in short-term debt - net
Cash dividends to ExxonMobil shareholders
Net ExxonMobil shares sold/(acquired)
Net intercompany financing activity
All other financing, net	175	150
Net cash provided by/(used in) financing activities	175	150
Effects of exchange rate changes on cash
Increase/(decrease) in cash and cash equivalents
All Other Subsidiaries [Member]
Cash provided by/(used in) operating activities	26,577	(3,039)
Additions to property, plant and equipment	(13,526)	(10,166)
Sales of long-term assets	2,675	533
Net intercompany investing	(13,484)	21,383
All other investing, net	(2,509)	303
Net cash provided by/(used in) investing activities	(26,844)	12,053
Additions to long-term debt	249	33
Reductions in long-term debt	(43)	(16)
Additions/(reductions) in short-term debt - net	309	(657)
Cash dividends to ExxonMobil shareholders	(572)	(5,352)
Net ExxonMobil shares sold/(acquired)
Net intercompany financing activity	227	204
All other financing, net	(164)	(141)
Net cash provided by/(used in) financing activities	6	(5,929)
Effects of exchange rate changes on cash	388	(680)
Increase/(decrease) in cash and cash equivalents	127	2,405
Consolidating and Eliminating Adjustments [Member]
Cash provided by/(used in) operating activities	(573)	(5,352)
Additions to property, plant and equipment
Sales of long-term assets
Net intercompany investing	403	354
All other investing, net
Net cash provided by/(used in) investing activities	403	354
Additions to long-term debt
Reductions in long-term debt
Additions/(reductions) in short-term debt - net
Cash dividends to ExxonMobil shareholders	572	5,352
Net ExxonMobil shares sold/(acquired)
Net intercompany financing activity	(227)	(204)
All other financing, net	(175)	(150)
Net cash provided by/(used in) financing activities	170	4,998
Effects of exchange rate changes on cash
Increase/(decrease) in cash and cash equivalents