Leases (Lease Expense and Cash Outflows from Operating and Finance Leases) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Finance lease expense:
Depreciation and amortization	$ 2.1	$ 17.3
Interest expense	0.6	6.2
Total finance lease expense	2.7	23.5
Operating lease expense	62.5	59.3
Short-term lease expense	0.4	1.1
Variable lease expense	0.3	0.4
Total lease expense	65.9	84.3
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows from operating leases	79.3	59.9
Operating cash outflows from finance leases (interest component)	0.6	6.2
Financing cash outflows from finance leases (principal component)	4.0	2.4
Total cash outflows from operating and finance leases	$ 83.9	$ 68.5