v3.6.0.2
Debt - Summary of Effective Interest Rate, Contractual Interest Expense and Amortization of Debt Discount (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Debt Instrument [Line Items]      
Amortization of debt discount $ 34 $ 39 $ 3
2019 Cash Convertible Senior Notes [Member]      
Debt Instrument [Line Items]      
Effective interest rate 5.14% 5.14%  
Contractual interest expense $ 12 $ 12  
Amortization of debt discount $ 40 $ 38