Amount classified as property, plant and equipment attributable to disposal group held for sale or disposed of.

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Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

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The adjustment to reduce the value of existing agreements that specify the lessee's rights to use the leased property. This expense is charged when the estimates of future profits generated by the leased property are reduced.

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Disposals of Long-Lived Assets (Details Textual) - USD ($) $ in Millions		12 Months Ended
	Jun. 02, 2014	Dec. 31, 2015	Dec. 31, 2014	Jun. 01, 2014
Corporate and other [Member]
Impairment of Leasehold			$ 11.9
Eastern Oklahoma gas gathering assets [Member] \| SemGas [Member]
Proceeds from sale of property, plant and equipment	$ 2.4
Disposal group, including discontinued operation, property, plant and equipment				$ 22.5
Kansas gas gathering and compression assets [Member] \| SemGas [Member]
Proceeds from sale of property, plant and equipment		$ 1.0
Loss (gain) on impairment or disposal of long-lived assets, net [Member] \| Eastern Oklahoma gas gathering assets [Member] \| SemGas [Member]
Gain (loss) on disposal	$ (20.1)
Loss (gain) on impairment or disposal of long-lived assets, net [Member] \| Kansas gas gathering and compression assets [Member] \| SemGas [Member]
Gain (loss) on disposal		$ (1.7)