Share-Based Compensation - Compensation Expense Allocation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 16.0	$ 20.1	$ 59.5	$ 54.3
Related tax benefits	1.5	4.2	11.1	11.5
CoyCo 2
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense capitalized to deferred contract costs	9.2	1.7	12.7	5.4
Cost of services
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	6.9	12.4	30.8	32.1
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 9.1	$ 7.7	$ 28.7	$ 22.2