Supplemental Financial Data - Computer Software and Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Computer software
Balance at beginning of period	$ 557.4	$ 437.0
Acquisitions	0.0	79.3
Additions at cost	220.1	173.9
Amortization	(124.4)	(113.3)
Impairment / Write-off	(1.3)	(4.3)
Other	(20.0)	(15.2)
Balance at end of period	631.8	557.4
Goodwill
Balance at beginning of period	3,493.3	2,857.9
Acquisition	1.3	675.6
Impairment / Write-off	0.0	0.0
Other	(63.3)	(40.2)
Balance at end of period	$ 3,431.3	$ 3,493.3