Income Taxes (Components of income tax expense and reconciliation of effective tax rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current
Federal	$ 186	$ 13	$ 2
Foreign	10	15	42
State and local	24	14	5
Current income tax expense	220	42	49
Deferred
Federal	119	300	240
Foreign	(1)	5	2
State and local	5	31	19
Deferred income tax expense (benefit)	123	336	261
Total	343	378	310
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Computed tax at statutory tax rate	318	337	297
State income taxes, net of federal tax benefit	21	41	22
Non-deductible expenses and other	9	8	8
Foreign taxes	$ (5)	$ (8)	$ (17)