GOODWILL AND INTANGIBLE ASSETS (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 1,424.0	$ 1,420.9	$ 1,420.6
Foreign currency translation adjustment	0.4	0.3
Goodwill, Acquired During Period	2.7
Goodwill, Impairment Loss	0.0	0.0
Amortization	37.0	55.3	63.1
Chlor Alkali Products and Vinyls
Goodwill [Line Items]
Goodwill	1,276.1	1,275.8	1,275.6
Foreign currency translation adjustment	0.3	0.2
Goodwill, Acquired During Period	0.0
Goodwill, Impairment Loss				$ 557.6
Epoxy
Goodwill [Line Items]
Goodwill	145.2	145.1	145.0
Foreign currency translation adjustment	0.1	0.1
Goodwill, Acquired During Period	0.0
Goodwill, Impairment Loss				$ 142.2
Winchester
Goodwill [Line Items]
Goodwill	2.7	0.0	$ 0.0
Foreign currency translation adjustment	0.0	$ 0.0
Goodwill, Acquired During Period	$ 2.7