Income Taxes - Schedule of Composition of Net Deferred Tax Asset by Jurisdiction (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Deferred tax assets		$ 3,088
Valuation allowance		(1,755)
Deferred tax liabilities		(884)
Net deferred tax asset	$ 562	449
Domestic [Member]
Income Tax Disclosure [Line Items]
Deferred tax assets		1,346
Valuation allowance		(1,057)
Deferred tax liabilities		(272)
Net deferred tax asset		17
Foreign [Member]
Income Tax Disclosure [Line Items]
Deferred tax assets		1,742
Valuation allowance		(698)
Deferred tax liabilities		(612)
Net deferred tax asset		$ 432