Property, Plant and Equipment - Components of Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Land	$ 8.2	$ 11.5
Building and improvements	38.9	39.0
Pipeline and equipment	1,153.6	1,162.1
Other	17.8	17.9
Property, plant and equipment, gross	1,218.5	1,230.5
Accumulated depreciation, and amortization	(526.1)	(567.3)
Property plant and equipment excluding construction in progress	692.4	663.2
Construction in progress	44.1	79.2
Property, plant and equipment, net	736.5	$ 742.4
Assets under operating leases	365.8		$ 353.7
Assets under capital lease	22.8		22.8
Accumulated depreciation related to assets under operating leases	120.7		104.7
Accumulated depreciation related to assets under capital lease	$ 4.5		$ 3.0
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

Property plant and equipment excluding construction in progress.

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.

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The total charge for the use of long-lived depreciable assets subject to a lease meeting the criteria for capitalization.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount before accumulated depreciation, depletion and amortization of other physical assets used in the normal conduct of business to produce goods and services and not intended for resale.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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The amount of accumulated depreciation, by major property class, recorded on property subject to or available for lease as of the balance sheet date.

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Amount before accumulated depreciation of physical assets used in the normal conduct of business to produce goods and services subject to or available for lease.

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