GOODWILL AND INTANGIBLE ASSETS (Details 1) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2020	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Goodwill	$ 1,423.3	$ 1,420.9		$ 1,424.0	$ 1,420.9
Goodwill, Purchase Accounting Adjustments	(0.3)
Goodwill, Foreign Currency Translation Gain (Loss)	(0.4)	0.0
Chlor Alkali Products and Vinyls
Goodwill [Line Items]
Goodwill	1,275.8	1,275.8		1,276.1	1,275.8
Goodwill, Purchase Accounting Adjustments	0.0
Goodwill, Foreign Currency Translation Gain (Loss)	(0.3)	0.0
Goodwill, Impairment Loss			$ 557.6
Epoxy
Goodwill [Line Items]
Goodwill	145.1	145.1		145.2	145.1
Goodwill, Purchase Accounting Adjustments	0.0
Goodwill, Foreign Currency Translation Gain (Loss)	(0.1)	0.0
Goodwill, Impairment Loss			$ 142.2
Winchester
Goodwill [Line Items]
Goodwill	2.4	0.0		$ 2.7	$ 0.0
Goodwill, Purchase Accounting Adjustments	(0.3)
Goodwill, Foreign Currency Translation Gain (Loss)	$ 0.0	$ 0.0