Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax [Line Items]
Income tax expense (benefit)	$ 44		$ 19	$ (19)	$ 53
Effective income tax rate	99.50%		16.80%	30.70%	25.40%
Losses in jurisdictions	$ 44		$ 113	$ 60	$ 209
Tax benefit related to research and development credits and other incentives	(7)
Provision for income tax benefit at statutory income tax rate				117
Non-deductible transaction costs				16
Other items				8
Unrecognized tax benefits Increased during the period		$ 17
Jurisdiction [Member]
Income Tax [Line Items]
Losses in jurisdictions	$ (41)			$ (60)