Income Taxes (Income Tax Components) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income tax:
Federal	$ 509	$ 248	$ 549
State and local	36	33	24
Foreign	41	36	37
Total current income tax	586	317	610
Deferred income tax:
Federal	(124)	202	(102)
State and local	(4)	30	(10)
Foreign	(3)	(4)	(6)
Total deferred income tax	(131)	228	(118)
Total income tax provision	$ 455	$ 545	$ 492