RESTRUCTURING CHARGES (Details 1) $ in Millions	3 Months Ended		4 Months Ended	49 Months Ended	50 Months Ended	64 Months Ended	108 Months Ended
	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)	Oct. 21, 2021 T	Dec. 11, 2019 T
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 4.0	$ 8.3					$ 230.4
Inception to date Amounts Utilized (cash)							145.2
Inception to date Amounts Utilized (non-cash)							79.9
Epoxy
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.0	0.0
Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.0	0.0
Freeport 2024 Plan | Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 0.0
Additional restructuring and related expected cost	35.0		35.0	$ 35.0	$ 35.0	$ 35.0	35.0
Epoxy Optimization Plan | Epoxy
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.1	3.5					106.7
Additional restructuring and related expected cost	10.0		10.0	10.0	10.0	10.0	10.0
McIntosh Plan | Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.2	1.9		20.6
Additional restructuring and related expected cost	20.0		20.0	20.0	20.0	20.0	20.0
McIntosh Restructuring Capacity Reduction | T								400,000
Freeport 2021 Plan | Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.8	0.4			16.4
Additional restructuring and related expected cost	5.0		5.0	5.0	5.0	5.0	5.0
Freeport 2019 Plan | Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.9	$ 2.5				86.7
Additional restructuring and related expected cost	$ 10.0		$ 10.0	$ 10.0	$ 10.0	$ 10.0	$ 10.0
Freeport Chlor Alkali Capacity Reduction | T									230,000