Leases - Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease right-of-use assets	$ 367.6	$ 0.0
Finance lease assets	2.8
Total leased assets	370.4
Current operating lease liabilities	106.4	0.0
Current finance lease liabilities	0.3
Operating lease liabilities, noncurrent	240.5	$ 0.0
Finance lease liabilities, noncurrent	3.4
Present value of lease liabilities	$ 350.6