Employee Benefit Plans - Share-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	$ 189.6	$ 202.2	$ 217.1
Stock options
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	7.3	7.7	0.4
RSUs, RSAs, and PSAs
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	162.6	176.5	198.2
ESPP Purchase Rights
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	19.7	18.0	18.5
Cost of revenues - Product
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	5.4	5.7	6.3
Cost of revenues - Service
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	15.8	17.3	18.0
Research and development
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	78.8	94.0	120.6
Sales and marketing
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	58.2	56.0	51.1
General and administrative
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	$ 31.4	$ 29.2	$ 21.1