Segment Reporting - Geographic Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 3,009.5	$ 2,707.1	$ 2,438.1
Property, equipment and software, net	826.7	884.6
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,253.4	2,027.8	1,787.5
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,157.0	1,948.0	1,735.3
Property, equipment and software, net	652.8	684.3
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	632.9	585.2	564.6
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	542.3	583.6	564.6
Property, equipment and software, net	146.1	170.9
APJ
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	123.2	94.1	86.0
Other Foreign Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	310.2	175.5	$ 138.2
Property, equipment and software, net	$ 27.8	$ 29.4