SEGMENT INFORMATION (Details 1) - USD ($) $ in Millions	12 Months Ended				93 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2023
Sales [Abstract]
Sales	$ 6,833.0	$ 9,376.2	$ 8,910.6
Income (loss) before taxes [Abstract]
Income before taxes	(559.3)	(1,676.0)	(1,538.7)
Environmental expense	23.7	23.2	14.0
Restructuring charges	(89.6)	(25.3)	(27.9)		$ (386.2)
Goodwill, Impairment Loss	0.0	0.0
Other operating income	42.9	16.3	1.4
Interest expense	(181.1)	(143.9)	(348.0)
Interest income	4.3	2.2	0.2
Non-operating pension income	24.0	38.7	35.7
Depreciation and amortization expense [Abstract]
Total depreciation and amortization expense	533.4	598.8	582.5
Capital spending [Abstract]
Total capital spending	236.0	236.9	200.6
Assets
Total assets	7,713.2	8,044.2			7,713.2
Chlor Alkali Products and Vinyls
Sales [Abstract]
Sales	3,995.1	5,085.0	4,140.8
Income (loss) before taxes [Abstract]
Income before taxes	(664.2)	(1,181.3)	(997.8)
Goodwill, Impairment Loss				$ (557.6)
Depreciation and amortization expense [Abstract]
Total depreciation and amortization expense	440.7	482.2	466.4
Capital spending [Abstract]
Total capital spending	161.1	151.4	130.2
Assets
Total assets	5,650.2	5,782.2			5,650.2
Epoxy
Sales [Abstract]
Sales	1,329.2	2,690.5	3,186.0
Income (loss) before taxes [Abstract]
Income before taxes	31.0	(388.5)	(616.5)
Goodwill, Impairment Loss				$ (142.2)
Depreciation and amortization expense [Abstract]
Total depreciation and amortization expense	57.4	83.3	86.1
Capital spending [Abstract]
Total capital spending	15.2	27.2	31.0
Assets
Total assets	979.3	1,201.9			979.3
Winchester
Sales [Abstract]
Sales	1,508.7	1,600.7	1,583.8
Income (loss) before taxes [Abstract]
Income before taxes	(255.6)	(372.9)	(412.1)
Depreciation and amortization expense [Abstract]
Total depreciation and amortization expense	27.2	24.6	23.3
Capital spending [Abstract]
Total capital spending	33.3	31.0	28.5
Assets
Total assets	683.6	595.0			683.6
Corporate/Other
Income (loss) before taxes [Abstract]
Environmental expense	(23.7)	(23.2)	(14.0)
Other corporate and unallocated costs	(106.3)	(131.5)	(135.1)
Restructuring charges	(89.6)	(25.3)	(27.9)
Depreciation and amortization expense [Abstract]
Total depreciation and amortization expense	8.1	8.7	6.7
Capital spending [Abstract]
Total capital spending	26.4	27.3	$ 10.9
Assets
Total assets	$ 400.1	$ 465.1			$ 400.1