SEGMENT INFORMATION (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 segment	Dec. 31, 2012	Dec. 31, 2011
Segment information
Number of reportable segments									3
Segment information
Total net sales	$ 1,134.5	$ 1,197.5	$ 1,272.8	$ 1,061.2	$ 784.7	$ 813.5	$ 867.7	$ 859.9	$ 4,666.0	$ 3,325.8	$ 3,222.9
Transaction related costs and other, net									35.6	38.9	3.3
Long-lived asset impairment charges, net									36.0	(0.8)	8.3
Gain on sale of assets										(19.3)	(1.1)
Operating income	96.9	78.1	124.6	71.2	67.6	73.9	28.4	68.2	370.8	238.1	124.6
Depreciation and amortization									148.3	82.0	91.4
Capital expenditures									196.1	80.3	66.4
Total assets	5,877.2				1,801.3				5,877.2	1,801.3	1,644.2
Operating segments
Segment information
Total net sales									4,666.0	3,325.7	3,222.9
Chlorovinyls
Segment information
Total net sales									2,917.3	1,344.9	1,318.7
Transaction related costs and other, net									(8.7)	1.3	0.5
Gain on sale of assets										(19.3)	(1.1)
Operating income									434.9	237.2	143.3
Depreciation and amortization									174.2	45.2	56.0
Capital expenditures									132.7	44.7	37.1
Total assets	5,074.0				966.4				5,074.0	966.4	874.6
Chlorovinyls | Operating segments
Segment information
Total net sales									3,143.5	1,581.0	1,554.4
Chlorovinyls | Intersegment elimination
Segment information
Total net sales									226.2	236.1	235.7
Building Products
Segment information
Number of primary product groups									2
Segment information
Total net sales									849.9	876.6	883.9
Transaction related costs and other, net									3.2	1.5	2.8
Long-lived asset impairment charges, net									28.5	(0.8)	8.3
Operating income									3.0	18.4	7.5
Depreciation and amortization									35.7	38.4	39.7
Capital expenditures									44.4	24.9	23.8
Total assets	577.8				604.5				577.8	604.5	606.4
Building Products | Operating segments
Segment information
Total net sales									850.0	877.0	883.9
Building Products | Intersegment elimination
Segment information
Total net sales									0.1	0.4
Aromatics
Segment information
Total net sales									898.8	1,104.3	1,020.3
Operating income									29.1	64.6	10.4
Depreciation and amortization									1.2	1.5	1.5
Capital expenditures									7.1	2.7	1.6
Total assets	146.8				180.1				146.8	180.1	121.3
Aromatics | Operating segments
Segment information
Total net sales									898.8	1,104.3	1,020.3
Eliminations, Unallocated and Other
Segment information
Transaction related costs and other, net									41.1	36.1
Long-lived asset impairment charges, net									7.5
Operating income									(96.2)	(82.1)	(36.6)
Depreciation and amortization									6.9	4.7	4.3
Capital expenditures									11.9	8.0	3.9
Total assets	78.6				50.3				78.6	50.3	41.9
Eliminations, Unallocated and Other | Operating segments
Segment information
Total net sales									(226.3)	(236.5)	(235.7)
Eliminations, Unallocated and Other | Intersegment elimination
Segment information
Total net sales									$ (226.3)	$ (236.5)	$ (235.7)