Leases Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Finance lease cost:
Total lease cost	$ 14.6	$ 29.6
Equipment costs [Member]
Lease Cost [Line Items]
Operating lease cost	13.4	27.2
Depreciation and amortization [Member]
Finance lease cost:
Amortization of finance lease assets	0.9	1.8
Interest expense [Member]
Finance lease cost:
Interest on lease liabilities	$ 0.3	$ 0.6