Income Taxes - Components of Deferred Provision (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred income tax provision (excluding the effects of other components)	$ (140)	$ 201	$ 144
Decrease in Federal operating loss carryforwards	0	0	1
(Decrease) increase in State valuation allowance	0	(5)	11
Increase in State capital loss carryforwards	0	(6)	0
(Increase) decrease in foreign and general business tax credits	0	0	29
Deferred income tax provision (benefit)	$ (140)	$ 190	$ 185