v3.26.1
GOODWILL AND INTANGIBLE ASSETS (Details 1) - USD ($)
$ in Millions
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2022
Dec. 31, 2025
Dec. 31, 2024
Goodwill [Line Items]          
Goodwill $ 1,427.7 $ 1,425.5   $ 1,427.6 $ 1,423.6
Goodwill, Foreign Currency Translation Gain (Loss) 0.1 (0.1)      
Goodwill, Period Increase (Decrease)   2.0      
Chlor Alkali Products and Vinyls          
Goodwill [Line Items]          
Goodwill 1,276.4 1,276.3   1,276.3 1,276.4
Goodwill, Foreign Currency Translation Gain (Loss) 0.1 (0.1)      
Goodwill, Impairment Loss     $ 557.6    
Goodwill, Period Increase (Decrease)   0.0      
Epoxy          
Goodwill [Line Items]          
Goodwill 144.8 144.8   144.8 144.8
Goodwill, Foreign Currency Translation Gain (Loss) 0.0 0.0      
Goodwill, Impairment Loss     $ 142.2    
Goodwill, Period Increase (Decrease)   0.0      
Winchester          
Goodwill [Line Items]          
Goodwill 6.5 4.4   $ 6.5 $ 2.4
Goodwill, Foreign Currency Translation Gain (Loss) $ 0.0 0.0      
Goodwill, Period Increase (Decrease)   $ 2.0