Leases - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finance lease costs
Amortization of lease right of use assets	$ 3.9	$ 2.9
Interest on lease liabilities	1.1	0.9
Operating lease costs	75.1	60.5
Short-term lease costs	16.1	22.0
Variable lease costs	7.0	10.6
Total lease costs	$ 103.2	$ 96.9