Leases - Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease right-of-use assets	$ 373.9	$ 0.0
Finance lease assets	2.7
Total leased assets	376.6
Current operating lease liabilities	110.5	0.0
Current finance lease liabilities	0.2
Operating lease liabilities, noncurrent	243.7	$ 0.0
Finance lease liabilities, noncurrent	3.4
Present value of lease liabilities	$ 357.8