Segments - Revenue by Product (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Total net revenues	$ 998.0	$ 1,001.7
Product
Segment Reporting Information [Line Items]
Total net revenues	608.8	618.7
Routing
Segment Reporting Information [Line Items]
Total net revenues	314.5	374.7
Switching
Segment Reporting Information [Line Items]
Total net revenues	219.8	176.4
Security
Segment Reporting Information [Line Items]
Total net revenues	74.5	67.6
Service
Segment Reporting Information [Line Items]
Total net revenues	$ 389.2	$ 383.0