Income Taxes - Components (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal									$ 191	$ 3	$ (35)
State and local									27	35	(222)
Foreign									11	2	16
Total current									229	40	(241)
Deferred									(140)	190	185
Total income tax expense (benefit)	$ (11)	$ 26	$ (5)	$ 79	$ (55)	$ 111	$ 98	$ 76	$ 89	$ 230	$ (56)