Income Taxes - Difference Between Effective Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended							12 Months Ended
	Dec. 31, 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
Income Tax Disclosure [Abstract]
Income tax provision (benefit) at federal statutory rate								$ (81)	$ (181)	$ 62
Foreign tax rate differential								2	(1)	(6)
State income tax provision (benefit), net of federal benefit								(3)	(8)	3
Nondeductible expenses								8	3	2
Foreign tax credits								(2)	(3)
Nondeductible goodwill impairment									42
Change in valuation allowance								78	129
Change in contingency reserve and other								2	3	1
Income tax provision (benefit)	$ 23	$ (15)	$ (4)	$ 63	$ (67)	$ (10)	$ (2)	$ 4	$ (16)	$ 62
Effective tax rate								(1.60%)	3.00%	34.90%