EARNINGS PER SHARE (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Numerator
Net income (loss) attributable to Axiall	$ (3.5)	$ 35.3
Less : Net income attributable to participating securities		0.5
Net income (loss) attributable to common stockholders	$ (3.5)	$ 34.8
Denominator
Weighted average common shares outstanding - Basic	59.3	34.2
Plus : Dilutive effect of stock options and awards (in shares)		0.2
Weighted average common shares outstanding - Diluted	59.3	34.4
Earnings (loss) per common share attributable to Axiall:
Basic (in dollars per share)	$ (0.06)	$ 1.02
Diluted (in dollars per share)	$ (0.06)	$ 1.01