Amount of amortization recognized in connection with the Ethylene Supply Agreement.

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Average remaining life expectancy of inactive participants.

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Amount of other assets acquired at the acquisition date in connection with the Ethylene Supply Agreement and expected to be realized.

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Expense for earn out liability.

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The gain recorded in other operating income due to insurance recoveries for property damage and business interruption at the Becancour, Canada chlor alkali facility.

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The gain recorded in other operating income due to insurance recoveries for property damage and business interruption at the McIntosh, AL chlor alkali facility.

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The amount of upfront payments made upon the closing of the Transactions in order to receive ethylene at producer economics and for certain reservation fees for obtaining additional future ethylene supply at producer economics.

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Additional payments to TDCC related to the supply of Ethylene at producer economics expected to occur in the fourth quarter of 2017.

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Additional payments to TDCC related to the supply of Ethylene at producer economics expected to occur in the fourth quarter of 2020.

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Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

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Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Amount of gain (loss) on sale or disposal of an equity method investment.

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Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

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ACCOUNTING POLICIES (Detail Textuals) $ in Millions		3 Months Ended	12 Months Ended
ACCOUNTING POLICIES (Detail Textuals) $ in Millions	Oct. 05, 2015 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Feb. 28, 2011
Business Combination, Separately Recognized Transactions [Line Items]
Gain in Other Operating Income due to Insurance Recoveries at Becancour			$ 42.3
Gain in Other Operating Income due to Insurance Recoveries at McIntosh			3.7
Expense for earnout liability					$ 7.9
Business Acquisition, Percentage of Voting Interests Acquired						50.00%
Gain (Loss) on Sale of Equity Investments			0.0	$ 0.0	6.5
Asset retirement obligation non-current			46.2	44.2
Asset Retirement Obligation, Revision of Estimate			3.1	2.0
Goodwill and Intangible Asset Impairment			0.0	$ 0.0	$ 0.0
Up-front payments under the ethylene agreements	$ 433.5
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Ethylene Asset	$ 410.8
Amortization of Supply Contracts		$ 4.3	$ 4.3
Average remaining life expectancy of the inactive participants in the defined benefit pension plan (in years)			19	18
Minimum
Business Combination, Separately Recognized Transactions [Line Items]
Q4 2017 Supply Contract Payment			$ 230.0
Q4 2020 Supply Contract Payment			425.0
Maximum
Business Combination, Separately Recognized Transactions [Line Items]
Q4 2017 Supply Contract Payment			250.0
Q4 2020 Supply Contract Payment			$ 465.0