Goodwill and Intangible Assets - Schedule of Computer Software and Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024
Computer software
Balance at beginning of period	$ 691.8	$ 676.3	$ 671.4	$ 666.3
Additions at cost	48.4	53.4	54.9	52.5
Amortization	(53.7)	(50.1)	(41.4)	(40.7)
Impairment / Write-off			(0.2)
Other	17.9	12.2	0.0	(6.7)
Balance at end of period	704.4	691.8	684.7	671.4
Goodwill
Balance at beginning of period	3,445.0	3,409.8	3,424.7	3,445.8
Other	32.8	35.2	1.9	(21.1)
Balance at end of period	$ 3,477.8	$ 3,445.0	$ 3,426.6	$ 3,424.7