Freeport, TX chlor alkali production capacity reduction announced on December 11, 2019.

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Reduction of diaphragm-grade chlor alkali capacity at our McIntosh, AL facility announced in 2021.

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RESTRUCTURING CHARGES (Details 1) $ in Millions	3 Months Ended						9 Months Ended		64 Months Ended	123 Months Ended
RESTRUCTURING CHARGES (Details 1) $ in Millions	Sep. 30, 2026 USD ($)	Jun. 30, 2026 USD ($)	Mar. 31, 2026 USD ($)	Sep. 30, 2025 USD ($)	Jun. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Sep. 30, 2026 USD ($)	Sep. 30, 2025 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2026 USD ($)	Oct. 21, 2021 T	Dec. 11, 2019 T
Restructuring Cost and Reserve [Line Items]
McIntosh Restructuring Capacity Reduction \| T											400,000
Freeport Chlor Alkali Capacity Reduction \| T												230,000
Restructuring charges	$ 1.7	$ 10.5	$ 9.1	$ 2.9	$ 7.4	$ 4.0	$ 21.3	$ 14.3	$ 281.2
Additional restructuring and related expected cost	70.0						70.0
Inception to date Amounts Utilized (cash)										$ 180.7
Inception to date Amounts Utilized (non-cash)										$ 86.5
Epoxy
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.0			0.0			0.0	0.0	122.8
Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.0			$ 0.0			$ 0.0	$ 0.0	$ 155.3