Employee Benefit Plans - Schedule of Share Based Compensation Expenses (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Share-based compensation expense included in operating expenses | $ 106.2 | $ 110.8 | $ 82.7 |
| Cost of sales | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Share-based compensation expense included in operating expenses | 9.6 | 12.0 | 8.1 |
| Research and development | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Share-based compensation expense included in operating expenses | 37.5 | 39.8 | 28.5 |
| Selling, general and administrative | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Share-based compensation expense included in operating expenses | $ 59.1 | $ 59.0 | $ 46.1 |