SEGMENT INFORMATION (Details 1) - USD ($) $ in Millions	3 Months Ended						9 Months Ended		78 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022
Sales [Abstract]
Sales	$ 2,321.7			$ 2,340.1			$ 7,399.2	$ 6,480.2
Income before taxes:
Income (loss) before taxes	367.9			504.3			1,432.2	1,147.7
Corporate/Other:
Environmental expense	7.4			3.6			18.0	10.8
Restructuring charges	(7.6)	$ (3.6)	$ (3.1)	(3.6)	$ (14.0)	$ (6.9)	(14.3)	(24.5)	$ (285.6)
Other operating income (expense)	13.0			(0.5)			16.3	0.0
Interest expense	(36.0)			(54.0)			(103.4)	(204.4)
Interest income	0.5			0.1			1.2	0.2
Non-operating pension income	9.9			9.2			29.0	26.7
Corporate/other
Corporate/Other:
Environmental expense	7.4			3.6			18.0	8.6
Other corporate and unallocated costs	(27.5)			(36.8)			(92.8)	(100.7)
Restructuring charges	(7.6)			(3.6)			(14.3)	(24.5)
Chlor Alkali Products and Vinyls
Sales [Abstract]
Sales	1,263.5			1,062.4			3,912.2	2,896.7
Income before taxes:
Income (loss) before taxes	253.9			263.0			929.0	703.0
Epoxy
Sales [Abstract]
Sales	644.1			877.7			2,206.3	2,390.3
Income before taxes:
Income (loss) before taxes	80.1			215.2			358.0	445.7
Winchester
Sales [Abstract]
Sales	414.1			400.0			1,280.7	1,193.2
Income before taxes:
Income (loss) before taxes	$ 89.0			$ 115.3			$ 327.2	$ 310.3