Litigation And Other Contingencies (Narrative) (Details) (USD $)	Dec. 31, 2011	Dec. 23, 2011 days	Jun. 30, 2011 gal	May 01, 2007	Dec. 31, 2011 Equity Company Obligations [Member]		Jun. 27, 2007 Expropriation Of Assets [Member]	Jun. 30, 2011 Compensatory Damages [Member]	Jun. 30, 2011 Punitive Damages [Member]	Feb. 13, 2012 Mobil Cerro Negro, Ltd. (MCN) [Member]	Dec. 23, 2011 Mobil Cerro Negro, Ltd. (MCN) [Member]	Oct. 24, 2011 Production Sharing Contract (PSC) [Member]	Feb. 01, 2012 Settlement Of Litigation [Member] Mobil Cerro Negro, Ltd. (MCN) [Member]	Oct. 24, 2011 Pending Or Threatened Litigation [Member]
Loss Contingencies [Line Items]
Accidental gasoline leak (gallons)			26,000
Litigation court verdict								$ 497,000,000	$ 1,000,000,000
Guarantees	8,456,000,000				4,607,000,000	[1]
Percentage ownership interest in Cerro Negro Project				41.67%			41.67%
Net book investment in Cerro Negro Project	750,000,000
Amount awarded for contractual obligations, before deductions											908,000,000
Amount arbitration award reduced by due to debt owed to PDVSA and PdVSA CN											161,000,000
Arbitration awarded for contractual obligations after debt deducted											747,000,000
Number of days to comply with arbitration verdict		60
Partial payment of arbitration awarded for breach of contractual obligations													305,000,000
Cancellation of bond debt										195,000,000
Percent interest in Erha block PSC												56.25%
Amount of award relating to excess lifting of crude oil														1,800,000,000
Accrued interest relating to award for excess lifting of crude oil														$ 234,000,000

[1] ExxonMobil share.