Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 3,520	$ 3,235	$ 2,716
State	306	(397)	157
Foreign	966	723	774
Total	4,792	3,561	3,647
Deferred:
Federal	(70)	(198)	29
State	0	(43)	6
Foreign	(50)	(17)	(43)
Total	(120)	(258)	(8)
Provision for income taxes	$ 4,672	$ 3,303	$ 3,639