Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from finance leases	$ 15.4
Operating cash flows from operating leases	403.6
Financing cash flows from finance leases	$ 6.2	$ 0.0	$ 0.0