SEGMENT INFORMATION (Details 1) - USD ($) $ in Millions	3 Months Ended				6 Months Ended		75 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022
Sales [Abstract]
Sales	$ 2,616.1		$ 2,221.3		$ 5,077.5	$ 4,140.1
Income before taxes:
Income (loss) before taxes	540.7		337.3		1,064.3	643.4
Corporate/Other:
Environmental expense	5.0		4.7		10.6	7.2
Restructuring charges	(3.6)	$ (3.1)	(14.0)	$ (6.9)	(6.7)	(20.9)	$ (278.0)
Other operating income	3.3		0.5		3.3	0.5
Interest expense	(34.5)		(65.9)		(67.4)	(150.4)
Interest income	0.3		0.0		0.7	0.1
Non-operating pension income	9.5		8.2		19.1	17.5
Corporate/other
Corporate/Other:
Environmental expense	5.0		4.7		10.6	5.0
Other corporate and unallocated costs	(35.0)		(30.9)		(65.3)	(63.9)
Restructuring charges	(3.6)		(14.0)		(6.7)	(20.9)
Chlor Alkali Products and Vinyls
Sales [Abstract]
Sales	1,403.5		967.3		2,648.7	1,834.3
Income before taxes:
Income (loss) before taxes	346.5		168.9		675.1	440.0
Epoxy
Sales [Abstract]
Sales	772.7		850.0		1,562.2	1,512.6
Income before taxes:
Income (loss) before taxes	139.9		165.3		277.9	230.5
Winchester
Sales [Abstract]
Sales	439.9		404.0		866.6	793.2
Income before taxes:
Income (loss) before taxes	$ 119.3		$ 109.9		$ 238.2	$ 195.0