Assets Held For Sales (Narrative) (Details) (USD $) In Billions, except Share data in Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Assets Held For Sales [Abstract]
Noncontrolling Interest, Ownership Percentage by Parent	50.00%
Payment for shares of ExxonMobil Yugen Kaisha (ExxonMobil wholly-own parent of TonenGeneral)	$ 3.9
Shares of TonenGeneral owned by ExxonMobil Yugen Kaisha when sold	200
Corporation's ownership percentage of TonenGeneral after TonenGeneral acquisition of ExxonMobil Yugen Kaisha	22.00%