SEGMENT INFORMATION (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Sales	$ 6,833.0	$ 9,376.2	$ 8,910.6
U.S.
Disaggregation of Revenue [Line Items]
Sales	4,599.4	5,722.1	5,268.0
Europe
Disaggregation of Revenue [Line Items]
Sales	603.7	1,547.8	1,680.8
Other foreign
Disaggregation of Revenue [Line Items]
Sales	1,629.9	2,106.3	1,961.8
Chlor Alkali Products and Vinyls
Disaggregation of Revenue [Line Items]
Sales	3,995.1	5,085.0	4,140.8
Chlor Alkali Products and Vinyls | Caustic soda
Disaggregation of Revenue [Line Items]
Sales	1,790.0	2,389.1	1,869.3
Chlor Alkali Products and Vinyls | Chlorine, chlorine derivatives and other products
Disaggregation of Revenue [Line Items]
Sales	2,205.1	2,695.9	2,271.5
Chlor Alkali Products and Vinyls | U.S.
Disaggregation of Revenue [Line Items]
Sales	2,700.0	3,400.0	2,839.1
Chlor Alkali Products and Vinyls | Europe
Disaggregation of Revenue [Line Items]
Sales	207.9	331.9	203.5
Chlor Alkali Products and Vinyls | Other foreign
Disaggregation of Revenue [Line Items]
Sales	1,087.2	1,353.1	1,098.2
Epoxy
Disaggregation of Revenue [Line Items]
Sales	1,329.2	2,690.5	3,186.0
Epoxy | Aromatics and allylics
Disaggregation of Revenue [Line Items]
Sales	525.1	1,338.6	1,450.5
Epoxy | Epoxy resins
Disaggregation of Revenue [Line Items]
Sales	804.1	1,351.9	1,735.5
Epoxy | U.S.
Disaggregation of Revenue [Line Items]
Sales	562.8	855.1	926.7
Epoxy | Europe
Disaggregation of Revenue [Line Items]
Sales	338.5	1,181.8	1,457.9
Epoxy | Other foreign
Disaggregation of Revenue [Line Items]
Sales	427.9	653.6	801.4
Winchester
Disaggregation of Revenue [Line Items]
Sales	1,508.7	1,600.7	1,583.8
Winchester | Commercial
Disaggregation of Revenue [Line Items]
Sales	806.5	1,079.1	1,104.1
Winchester | Military and law enforcement
Disaggregation of Revenue [Line Items]
Sales	702.2	521.6	479.7
Winchester | U.S.
Disaggregation of Revenue [Line Items]
Sales	1,336.6	1,467.0	1,502.2
Winchester | Europe
Disaggregation of Revenue [Line Items]
Sales	57.3	34.1	19.4
Winchester | Other foreign
Disaggregation of Revenue [Line Items]
Sales	$ 114.8	$ 99.6	$ 62.2