Restructuring and Reorganization Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Mar. 31, 2010 Person	Sep. 30, 2011 Person LegalMatter
Restructuring and reorganization
Balance at December 31, 2010		$ 138
Adjustment		(21)
Payments		(62)
Balance at September 30, 2011		55
Restructuring and Reorganization (Textual) [Abstract]
Employees in downstream expected to be terminated	2,900
Number of affected employees located in country	1,300
Number of employees terminated		2,300
Before-tax charges of restructuring and reorganization costs recorded in the first quarter of 2010	244
Beginning restructuring reserves		55
Payments		$ 62