Segments - Revenues by Customer Vertical (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Total net revenues	$ 1,221.0	$ 1,097.9
Cloud
Segment Reporting Information [Line Items]
Total net revenues	331.6	264.8
Telecom/Cable
Segment Reporting Information [Line Items]
Total net revenues	568.5	518.1
Strategic Enterprise
Segment Reporting Information [Line Items]
Total net revenues	$ 320.9	$ 315.0