GOODWILL AND INTANGIBLES (Details 1) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$ 2,186.3	$ 747.1	$ 2,174.1	$ 747.1
Acquisition activity	11.9	0.0
Foreign currency translation adjustment	0.3
Chlor Alkali Products and Vinyls Segment
Goodwill [Line Items]
Goodwill	1,887.4	747.1	1,877.5	747.1
Acquisition activity	9.7	0.0
Foreign currency translation adjustment	0.2
Epoxy Segment
Goodwill [Line Items]
Goodwill	298.9	0.0	$ 296.6	$ 0.0
Acquisition activity	2.2	$ 0.0
Foreign currency translation adjustment	$ 0.1

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 1
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+ References

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-SubTopic 20
-Section 50
-Paragraph 1
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