Leases - Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease expense	$ 24.0	$ 65.2
Finance lease expense:
Amortization of right-of-use assets	2.1	6.3
Interest on lease obligations	1.2	3.6
Total lease expense	$ 27.3	$ 75.1