Leases Leases - Supplemental balance sheet (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets	$ 269.3	$ 0.0
Finance lease assets	151.3
Total lease assets	420.6
Current liabilities operating leases	64.3
Current liabilities financing leases	29.3
Noncurrent liabilities operating leases	217.9	$ 0.0
Noncurrent liabilities financing leases	110.4
Total lease liabilities	$ 421.9