Income Taxes (Income Tax Components) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income tax:
Federal	$ 245	$ 509	$ 248
State and local	44	36	33
Foreign	23	41	36
Total current income tax	312	586	317
Deferred income tax:
Federal	(36)	(124)	202
State and local	3	(4)	30
Foreign	(1)	(3)	(4)
Total deferred income tax	(34)	(131)	228
Total income tax provision	$ 278	$ 455	$ 545