Income Taxes - Deferred Tax Assets and Liabilities, Net (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred income taxes (long-term asset)	$ 2,653	$ 2,371
Deferred income taxes (long-term liability)	(1,334)	(1,838)
Net deferred tax assets	$ 1,319	$ 533