SEGMENT INFORMATION (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Sales by Product Line
Total net sales	$ 1,061.2	$ 859.9
Chlorovinyls
Sales by Product Line
Total net sales	614.5	329.5
Chlorovinyls | Chlor-alkali and derivative products
Sales by Product Line
Total net sales	488.6	207.5
Chlorovinyls | Compound products
Sales by Product Line
Total net sales	125.9	122.0
Building Products
Sales by Product Line
Total net sales	162.2	187.2
Building Products | Window and door profiles and moulding products
Sales by Product Line
Total net sales	63.0	66.8
Building Products | Outdoor building products
Sales by Product Line
Total net sales	99.2	120.4
Aromatics
Sales by Product Line
Total net sales	284.5	343.2
Aromatics | Cumene products
Sales by Product Line
Total net sales	170.1	251.8
Aromatics | Phenol and acetone products
Sales by Product Line
Total net sales	$ 114.4	$ 91.4