SEGMENT INFORMATION (Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Sales	$ 1,702.7	$ 2,616.1	$ 3,547.0	$ 5,077.5
Chlor Alkali Products and Vinyls
Disaggregation of Revenue [Line Items]
Sales	1,002.3	1,403.5	2,119.4	2,648.7
Chlor Alkali Products and Vinyls | Caustic soda
Disaggregation of Revenue [Line Items]
Sales	454.9	635.1	1,001.7	1,154.0
Chlor Alkali Products and Vinyls | Chlorine, chlorine-derivatives and other co-products
Disaggregation of Revenue [Line Items]
Sales	547.4	768.4	1,117.7	1,494.7
Epoxy
Disaggregation of Revenue [Line Items]
Sales	333.8	772.7	694.5	1,562.2
Epoxy | Aromatics and allylics
Disaggregation of Revenue [Line Items]
Sales	128.7	384.1	271.0	776.1
Epoxy | Epoxy resins
Disaggregation of Revenue [Line Items]
Sales	205.1	388.6	423.5	786.1
Winchester
Disaggregation of Revenue [Line Items]
Sales	366.6	439.9	733.1	866.6
Winchester | Commercial
Disaggregation of Revenue [Line Items]
Sales	199.4	320.6	399.9	634.8
Winchester | Military and law enforcement
Disaggregation of Revenue [Line Items]
Sales	$ 167.2	$ 119.3	$ 333.2	$ 231.8