GOODWILL, OTHER INTANGIBLE ASSETS AND RESTRUCTURING (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	$ 1,255.4	$ 1,255.4		$ 1,255.4
Accumulated impairment charges	(2.6)
Accumulated amortization:	(152.0)	(82.7)		(152.0)
Foreign currency translation adjustment:	(14.2)	(4.0)
Net carrying amounts	1,086.6	1,168.7		1,086.6
Amortization expense for the definite-lived intangible assets	69.6	64.3	3.3
Total definite-lived intangible asset estimated annual amortization expense for the next five fiscal years
Year one	67.0			67.0
Year two	67.0			67.0
Year three	67.0			67.0
Year four	67.0			67.0
Year five	67.0			67.0
Customer relationships
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	1,174.5	1,174.5		1,174.5
Accumulated amortization:	(133.2)	(68.7)		(133.2)
Foreign currency translation adjustment:	(14.2)	(4.0)
Net carrying amounts	1,024.5	1,101.8		1,024.5
Customer relationships | Weighted average
Changes made to finite-lived intangible assets by reportable segment
Weighted average estimated useful life	16 years
Supply contracts
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	42.6	42.6		42.6
Accumulated amortization:	(4.1)	(2.0)		(4.1)
Net carrying amounts	38.5	40.6		38.5
Supply contracts | Weighted average
Changes made to finite-lived intangible assets by reportable segment
Weighted average estimated useful life	18 years
Trade names
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	6.0	6.0		6.0
Accumulated amortization:	(0.7)	(0.3)		(0.7)
Net carrying amounts	5.3	5.7		5.3
Trade names | Weighted average
Changes made to finite-lived intangible assets by reportable segment
Weighted average estimated useful life	15 years
Technology
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	32.3	32.3		32.3
Accumulated amortization:	(14.0)	(11.7)		(14.0)
Net carrying amounts	18.3	20.6		18.3
Technology | Weighted average
Changes made to finite-lived intangible assets by reportable segment
Weighted average estimated useful life	16 years
Chlorovinyls
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	1,205.8	1,205.8		1,205.8
Accumulated impairment charges	(2.6)
Accumulated amortization:	(127.2)	(61.1)		(127.2)
Foreign currency translation adjustment:	(14.2)	(4.0)
Net carrying amounts	1,061.8	1,140.7		1,061.8
Chlorovinyls | Customer relationships
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	1,142.3	1,142.3		1,142.3
Accumulated impairment charges				(2.6)
Accumulated amortization:	(121.1)	(58.2)		(121.1)
Foreign currency translation adjustment:	(14.2)	(4.0)
Net carrying amounts	1,004.4	1,080.1		1,004.4
Chlorovinyls | Supply contracts
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	42.6	42.6		42.6
Accumulated amortization:	(4.1)	(2.0)		(4.1)
Net carrying amounts	38.5	40.6		38.5
Chlorovinyls | Trade names
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	6.0	6.0		6.0
Accumulated amortization:	(0.7)	(0.3)		(0.7)
Net carrying amounts	5.3	5.7		5.3
Chlorovinyls | Technology
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	14.9	14.9		14.9
Accumulated amortization:	(1.3)	(0.6)		(1.3)
Net carrying amounts	13.6	14.3		13.6
Building Products
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	49.6	49.6		49.6
Accumulated amortization:	(24.8)	(21.6)		(24.8)
Net carrying amounts	24.8	28.0		24.8
Total definite-lived intangible asset estimated annual amortization expense for the next five fiscal years
Restructuring charge	6.3	3.2
Expected restructuring charges in 2014 and 2015	1.9			1.9
Building Products | Customer relationships
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	32.2	32.2		32.2
Accumulated amortization:	(12.1)	(10.5)		(12.1)
Net carrying amounts	20.1	21.7		20.1
Building Products | Technology
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	17.4	17.4		17.4
Accumulated amortization:	(12.7)	(11.1)		(12.7)
Net carrying amounts	4.7	6.3		4.7
Aromatics
Changes made to finite-lived intangible assets by reportable segment
Gross carrying amounts	$ 0	$ 0		$ 0