Leases (Schedule of Lease-Related Liabilities Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating lease liabilities:
Current portion included in accrued liabilities	$ 25.8
Noncurrent operating lease liabilities	235.2	$ 243.9	$ 0.0
Total operating lease liabilities	261.0
Financing lease liabilities:
Financing lease liabilities, current, prior to adoption of Topic 842			2.0
Financing lease liabilities, noncurrent, prior to adoption of Topic 842			28.8
Total financing lease liabilities			$ 30.8
Financing lease liabilities, current	1.0
Financing lease liabilities, noncurrent	29.3
Total financing lease liabilities	30.3
Total lease liabilities	$ 291.3
Weighted-average remaining lease term, operating leases	13 years
Weighted-average remaining lease term, finance leases	13 years
Weighted-average discount rate, operating leases	5.08%
Weighted-average discount rate, finance leases	5.81%