Leases - Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finance lease cost:
Amortization of right-of-use assets	$ 4.2
Interest on lease liabilities	0.5
Operating lease cost	53.2
Short-term lease cost	18.3
Variable lease cost	5.0
Sublease income	(11.4)
Total lease cost	$ 69.6
Rental expenses for properties and equipment		$ 48.7	$ 40.3