SEGMENT INFORMATION (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Sales	$ 2,616.1	$ 2,221.3	$ 5,077.5	$ 4,140.1
United States
Disaggregation of Revenue [Line Items]
Sales	1,600.4	1,340.8	3,064.6	2,441.1
Europe
Disaggregation of Revenue [Line Items]
Sales	453.7	449.5	885.7	802.8
Other foreign
Disaggregation of Revenue [Line Items]
Sales	562.0	431.0	1,127.2	896.2
Chlor Alkali Products and Vinyls
Disaggregation of Revenue [Line Items]
Sales	1,403.5	967.3	2,648.7	1,834.3
Chlor Alkali Products and Vinyls | United States
Disaggregation of Revenue [Line Items]
Sales	946.4	713.6	1,765.8	1,290.6
Chlor Alkali Products and Vinyls | Europe
Disaggregation of Revenue [Line Items]
Sales	82.4	39.4	152.8	68.9
Chlor Alkali Products and Vinyls | Other foreign
Disaggregation of Revenue [Line Items]
Sales	374.7	214.3	730.1	474.8
Epoxy
Disaggregation of Revenue [Line Items]
Sales	772.7	850.0	1,562.2	1,512.6
Epoxy | United States
Disaggregation of Revenue [Line Items]
Sales	252.8	253.6	495.7	411.9
Epoxy | Europe
Disaggregation of Revenue [Line Items]
Sales	354.5	403.8	713.4	723.8
Epoxy | Other foreign
Disaggregation of Revenue [Line Items]
Sales	165.4	192.6	353.1	376.9
Winchester
Disaggregation of Revenue [Line Items]
Sales	439.9	404.0	866.6	793.2
Winchester | United States
Disaggregation of Revenue [Line Items]
Sales	401.2	373.6	803.1	738.6
Winchester | Europe
Disaggregation of Revenue [Line Items]
Sales	16.8	6.3	19.5	10.1
Winchester | Other foreign
Disaggregation of Revenue [Line Items]
Sales	$ 21.9	$ 24.1	$ 44.0	$ 44.5