ACCUMULATED OTHER COMPREHENSIVE INCOME AND OTHER COMPREHENSIVE LOSS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	$ (73.7)
Other comprehensive income (loss) before reclassifications	(31.4)
Amounts reclassified from accumulated other comprehensive loss, net of tax	3.6
Other comprehensive loss attributable to Axiall, net of tax	(27.8)	(13.3)
Balance at the end of the period	(101.5)
Change in pension and OPEB liability adjustments
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(45.0)
Other comprehensive income (loss) before reclassifications	0.3
Amounts reclassified from accumulated other comprehensive loss, net of tax	(1.0)
Other comprehensive loss attributable to Axiall, net of tax	(0.7)
Balance at the end of the period	(45.7)
Change in foreign currency translation adjustment
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(20.4)
Other comprehensive income (loss) before reclassifications	(32.7)
Other comprehensive loss attributable to Axiall, net of tax	(32.7)
Balance at the end of the period	(53.1)
Change in derivative cash flow hedges
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(8.3)
Other comprehensive income (loss) before reclassifications	1.0
Amounts reclassified from accumulated other comprehensive loss, net of tax	4.6
Other comprehensive loss attributable to Axiall, net of tax	5.6
Balance at the end of the period	$ (2.7)