Property, Plant and Equipment - Components of Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Land	$ 8.2	$ 8.2
Building and improvements	38.9	29.6
Pipeline and equipment	1,153.6	1,145.0
Other	17.8	17.7
Property, plant and equipment, gross	1,218.5	1,200.5
Accumulated depreciation, and amortization	(526.1)	(495.8)
Property plant and equipment excluding construction in progress	692.4	704.7
Construction in progress	44.1	29.0
Property, plant and equipment, net	736.5	733.7	[1]
Assets under operating leases	353.7	343.9
Assets under capital lease	22.8	22.8
Accumulated depreciation related to assets under operating leases	104.7	91.2
Accumulated depreciation related to assets under capital lease	$ 3.0	$ 1.6
Building and Improvements | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, depreciable life	10 years
Building and Improvements | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, depreciable life	40 years
Pipeline and Equipment | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, depreciable life	10 years
Pipeline and Equipment | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, depreciable life	30 years
Other | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, depreciable life	5 years
Other | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, depreciable life	25 years

[1] The financial information presented has been retrospectively adjusted for acquisitions of businesses under common control.