Leases (Lease Expense and Cash Outflows from Operating and Finance Leases) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Finance lease expense:
Depreciation and amortization	$ 16.5	$ 19.7
Interest expense	6.5	8.5
Total finance lease expense	23.0	28.2
Operating lease expense	51.7	63.4
Short-term lease expense	1.1	1.8
Variable lease expense	1.1	0.8
Total lease expense	76.9	94.2
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows from operating leases	78.3	79.3
Operating cash outflows from finance leases (interest component)	6.5	8.5
Financing cash outflows from finance leases (principal component)	17.8	19.5
Total cash outflows from operating and finance leases	$ 102.6	$ 107.3