SEGMENT INFORMATION (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Sales	$ 1,671.4	$ 2,321.7	$ 5,218.4	$ 7,399.2
Chlor Alkali Products and Vinyls
Disaggregation of Revenue [Line Items]
Sales	969.6	1,263.5	3,089.0	3,912.2
Chlor Alkali Products and Vinyls | Caustic soda
Disaggregation of Revenue [Line Items]
Sales	422.3	598.4	1,424.0	1,752.4
Chlor Alkali Products and Vinyls | Chlorine, chlorine-derivatives and other co-products
Disaggregation of Revenue [Line Items]
Sales	547.3	665.1	1,665.0	2,159.8
Epoxy
Disaggregation of Revenue [Line Items]
Sales	321.6	644.1	1,016.1	2,206.3
Epoxy | Aromatics and allylics
Disaggregation of Revenue [Line Items]
Sales	116.9	316.8	387.9	1,092.9
Epoxy | Epoxy resins
Disaggregation of Revenue [Line Items]
Sales	204.7	327.3	628.2	1,113.4
Winchester
Disaggregation of Revenue [Line Items]
Sales	380.2	414.1	1,113.3	1,280.7
Winchester | Commercial
Disaggregation of Revenue [Line Items]
Sales	181.2	271.6	581.1	906.4
Winchester | Military and law enforcement
Disaggregation of Revenue [Line Items]
Sales	$ 199.0	$ 142.5	$ 532.2	$ 374.3