Leases (Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 14.1	$ 14.3
Operating cash flows from finance leases	0.1	0.1
Financing cash flows from finance leases	1.1	1.3
Leased assets obtained in exchange for lease obligations:
Operating leases	8.4	14.0
Finance leases	$ 0.0	$ 0.2