Income Taxes - Income Tax Expense (Benefit) on Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 0	$ 0	$ 0
Foreign	12	2	10
State	1	1	1
Income tax expense (benefit) on continuing operations	13	3	11
Deferred:
Federal	(621)	0	(2)
Foreign	(4)	4	2
State	(117)	0	0
Deferred income tax expense (benefit) on continuing operations	(742)	4	0
Provision for income tax expense	$ (729)	$ 7	$ 11