Effect of Changes in Fair Value Related to Derivative Instruments on Consolidated Statements of Income (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Expense [Member] | Currency Swap [Member]
Derivative [Line Items]
Effect on income of derivative instruments not designated as hedging instruments	$ (2)	$ 6	$ 0
Non Cash Convertible Debt Related Expense [Member]
Derivative [Line Items]
Effect on income of derivative instruments not designated as hedging instruments	(2)	6	0
Non Cash Convertible Debt Related Expense [Member] | Note Hedge [Member]
Derivative [Line Items]
Effect on income of derivative instruments not designated as hedging instruments	0	0	5
Non Cash Convertible Debt Related Expense [Member] | Cash Conversion Option [Member]
Derivative [Line Items]
Effect on income of derivative instruments not designated as hedging instruments	$ 0	$ 0	$ (5)