Employee Benefit Plans (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheet for pension and other postretirement benefit plans
Reserves for employee benefit plans	$ (9,156)	$ (6,696)
U.S. [Member]
Consolidated Balance Sheet for pension and other postretirement benefit plans
Deferred charges and other assets	5	7
Accrued liabilities	(72)	(134)
Reserves for employee benefit plans	(3,378)	(1,565)
Net amount recognized at December 31	(3,445)	(1,692)
International [Member]
Consolidated Balance Sheet for pension and other postretirement benefit plans
Deferred charges and other assets	116	77
Accrued liabilities	(84)	(71)
Reserves for employee benefit plans	(1,974)	(1,573)
Net amount recognized at December 31	(1,942)	(1,567)
Other Benefits [Member]
Consolidated Balance Sheet for pension and other postretirement benefit plans
Deferred charges and other assets	0	0
Accrued liabilities	(222)	(225)
Reserves for employee benefit plans	(3,543)	(3,380)
Net amount recognized at December 31	$ (3,765)	$ (3,605)