This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 35
-Paragraph 32
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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Loss recognized as a result of the initial and subsequent write-down of a long-lived asset's carrying amount to fair value.

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Supplemental Quarterly Data (Parenthetical) (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended						12 Months Ended
	Dec. 31, 2014	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impaired assets to be disposed of			$ 694.3	$ 610.8	$ 68.6		$ 83.3	$ 354.4
Gain from unconsolidated affiliates, net		$ 0.0				$ (0.8)		227.8	$ 35.1	$ (5.3)
Jackalope Gas Gathering Services, L.L.C.
Equity method investment, other than temporary impairment			51.4					51.4
Powder River Basin Industrial Complex, LLC
Equity method investment, other than temporary impairment			23.4					$ 23.4
Tres Palacios Holdings LLC
Impaired assets to be disposed of			$ 1,332.3	$ 610.8	$ 281.0		$ 83.3
Gain from unconsolidated affiliates, net	$ 30.6								$ 30.6