Employee Benefit Plans - Share-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	$ 202.2	$ 217.1	$ 187.5
Stock options
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	7.7	0.4	0.5
RSUs, RSAs, and PSAs
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	176.5	198.2	171.3
ESPP
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	18.0	18.5	15.7
Cost of revenues - Product
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	5.7	6.3	4.6
Cost of revenues - Service
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	17.3	18.0	17.5
Research and development
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	94.0	120.6	86.6
Sales and marketing
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	56.0	51.1	55.6
General and administrative
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	$ 29.2	$ 21.1	$ 23.2