Leases (Breakdown of Lease Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 192.1	$ 23.0	$ 17.9
Finance lease cost
Amortization of leased assets	11.3	10.2	10.8
Interest on lease liabilities	1.3	0.8	0.8
Short-term lease cost	17.0	12.2	10.0
Sublease income	(0.6)	(0.1)	0.0
Lease expense	$ 221.1	$ 46.1	$ 39.5