Segments - Revenues by Customer Vertical (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Total net revenues	$ 1,086.3	$ 1,102.5	$ 2,084.3	$ 2,104.2
Cloud
Segment Reporting Information [Line Items]
Total net revenues	285.5	285.0	547.4	508.2
Service Provider
Segment Reporting Information [Line Items]
Total net revenues	436.2	447.2	811.7	882.8
Enterprise
Segment Reporting Information [Line Items]
Total net revenues	$ 364.6	$ 370.3	$ 725.2	$ 713.2