Leases - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 42.3	$ 124.7
Short-term cost	4.5	11.4
Variable lease cost	1.9	5.2
Amortization of leased assets	0.1	0.3
Interest on lease liabilities	0.1	0.3
Total lease cost	$ 48.9	$ 141.9