Leases - Supplemental Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating cash flows from operating leases (a)	$ 37.9	$ 113.1
Operating cash flows from finance leases	0.1	0.3
Financing cash flows from finance leases	0.1	0.3
Leased assets obtained in exchange for new operating lease liabilities	$ 57.6	$ 111.4