Goodwill and Intangible Assets - Computer Software and Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021
Computer software
Balance at beginning of period	$ 563.4	$ 557.4	$ 508.1	$ 437.0
Acquisitions	0.0	0.0	(1.0)	65.0
Additions at cost	61.9	43.4	33.9	42.2
Amortization	(31.8)	(30.3)	(26.6)	(24.5)
Write-off			(0.7)	(3.1)
Other	(14.6)	(7.1)	2.8	(8.5)
Balance at end of period	578.9	563.4	516.5	508.1
Goodwill
Balance at beginning of period	3,475.4	3,493.3	3,318.2	2,857.9
Acquisitions	0.5	0.5	2.6	488.4
Other	(38.8)	(18.4)	10.3	(28.1)
Balance at end of period	$ 3,437.1	$ 3,475.4	$ 3,331.1	$ 3,318.2