Employee Benefit Plans (Details 2) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Before tax basis amount in accumulated other comprehensive loss.
Total recognized at December 31	$ 6,478	$ 7,417
U.S. [Member]
Before tax basis amount in accumulated other comprehensive loss.
Net actuarial loss	4,809	4,972
Prior service (credit) costs	(5)	(13)
Total recognized at December 31	4,804	4,959
International [Member]
Before tax basis amount in accumulated other comprehensive loss.
Net actuarial loss	1,143	1,487
Prior service (credit) costs	120	150
Total recognized at December 31	1,263	1,637
Other Benefits [Member]
Before tax basis amount in accumulated other comprehensive loss.
Net actuarial loss	367	763
Prior service (credit) costs	44	58
Total recognized at December 31	$ 411	$ 821