Segments - Revenues by Customer Vertical (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Total net revenues	$ 998.0	$ 1,001.7
Cloud
Segment Reporting Information [Line Items]
Total net revenues	261.9	223.1
Service Provider
Segment Reporting Information [Line Items]
Total net revenues	375.5	435.6
Enterprise
Segment Reporting Information [Line Items]
Total net revenues	$ 360.6	$ 343.0