Income Taxes (Components of income tax expense and reconciliation of effective tax rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current
Federal	$ 13	$ 2	$ 10
Foreign	15	42	39
State and local	14	5	2
Current income tax expense	42	49	51
Deferred
Federal	300	240	149
Foreign	5	2	4
State and local	31	19	14
Deferred income tax expense (benefit)	336	261	167
Total	378	310	218
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Computed tax at statutory tax rate	337	297	212
State income taxes, net of federal tax benefit	41	22	15
Non-deductible expenses and other	8	8	8
Foreign taxes	$ (8)	$ (17)	$ (17)