Employee Benefit Plans (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Before tax basis amount in accumulated other comprehensive loss.
Total recognized at December 31	$ 9,742	$ 9,279
U.S. [Member]
Before tax basis amount in accumulated other comprehensive loss.
Net actuarial loss	6,087	5,982
Prior service (credit) costs	58	(44)
Total recognized at December 31	6,145	5,938
International [Member]
Before tax basis amount in accumulated other comprehensive loss.
Net actuarial loss	2,439	2,250
Prior service (credit) costs	170	152
Total recognized at December 31	2,609	2,402
Other Benefits [Member]
Before tax basis amount in accumulated other comprehensive loss.
Net actuarial loss	968	1,002
Prior service (credit) costs	20	(63)
Total recognized at December 31	$ 988	$ 939