v3.26.1
SEGMENT INFORMATION (Details 1)
$ in Millions
 3 Months Ended 6 Months Ended 64 Months Ended
Jun. 30, 2026
USD ($)
Mar. 31, 2026
USD ($)
Jun. 30, 2025
USD ($)
Mar. 31, 2025
USD ($)
Jun. 30, 2026
USD ($)
sEGMENT
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Gross Margin [Abstract]                
Sales $ 1,741.9   $ 1,758.3   $ 3,324.9 $ 3,402.5    
Cost of goods sold 1,571.7   1,620.2   3,078.9 3,115.7    
Gross Profit 170.2   138.1   246.0 286.8    
Income (Loss) before Income Taxes [Abstract]                
Segment Reporting, Other Segment Item, Amount (103.7)   (96.6)   (250.1) (197.6)    
Restructuring charges (10.5) $ (9.1) (7.4) $ (4.0) (19.6) (11.4) $ (279.5)  
Other Operating Income (0.1)   (0.2)   (0.1) (0.2)    
Interest Expense, Operating and Nonoperating (44.3)   (45.6)   (86.4) (92.9)    
Non-operating pension income 2.6   4.9   6.1 10.6    
Income (loss) before taxes 3.8   (6.8)   (114.5) (4.7)    
Depreciation and amortization expense                
Depreciation and amortization 122.1   129.9   239.3 262.1    
Assets                
Assets 7,440.6   7,667.9   $ 7,440.6 7,667.9 7,440.6 $ 7,325.8
Number of Reportable Segments | sEGMENT         3      
United States                
Gross Margin [Abstract]                
Sales 1,211.0   1,201.9   $ 2,357.0 2,339.1    
Europe                
Gross Margin [Abstract]                
Sales 167.0   155.8   303.9 303.4    
Other foreign                
Gross Margin [Abstract]                
Sales 363.9   400.6   664.0 760.0    
Chlor Alkali Products and Vinyls                
Gross Margin [Abstract]                
Sales 819.5   979.5   1,576.4 1,904.0    
Cost of goods sold 726.5   871.8   1,453.6 1,673.8    
Gross Profit 93.0   107.7   122.8 230.2    
Income (Loss) before Income Taxes [Abstract]                
Segment Reporting, Other Segment Item, Amount (39.6)   (42.8)   (113.9) (87.0)    
Restructuring charges 0.0   0.0   0.0 0.0 (151.0)  
Other Operating Income 0.0   0.0   0.0 0.0    
Interest Expense, Operating and Nonoperating 0.0   0.0   0.0 0.0    
Non-operating pension income 0.0   0.0   0.0 0.0    
Income (loss) before taxes 53.4   64.9   8.9 143.2    
Depreciation and amortization expense                
Depreciation and amortization 98.1   106.3   191.3 213.5    
Assets                
Assets 5,118.1   5,277.4   5,118.1 5,277.4 5,118.1  
Chlor Alkali Products and Vinyls | United States                
Gross Margin [Abstract]                
Sales 558.4   664.2   1,109.2 1,311.1    
Chlor Alkali Products and Vinyls | Europe                
Gross Margin [Abstract]                
Sales 35.1   42.0   59.7 75.2    
Chlor Alkali Products and Vinyls | Other foreign                
Gross Margin [Abstract]                
Sales 226.0   273.3   407.5 517.7    
Epoxy                
Gross Margin [Abstract]                
Sales 422.1   331.2   777.7 662.9    
Cost of goods sold 391.3   340.0   734.4 685.1    
Gross Profit 30.8   (8.8)   43.3 (22.2)    
Income (Loss) before Income Taxes [Abstract]                
Segment Reporting, Other Segment Item, Amount (14.8)   (14.9)   (30.2) (29.9)    
Restructuring charges 0.0   0.0   0.0 0.0 (125.4)  
Other Operating Income 0.0   0.0   0.0 0.0    
Interest Expense, Operating and Nonoperating 0.0   0.0   0.0 0.0    
Non-operating pension income 0.0   0.0   0.0 0.0    
Income (loss) before taxes 16.0   (23.7)   13.1 (52.1)    
Depreciation and amortization expense                
Depreciation and amortization 11.7   13.1   23.6 25.9    
Assets                
Assets 934.1   949.3   934.1 949.3 934.1  
Epoxy | United States                
Gross Margin [Abstract]                
Sales 196.8   140.8   348.4 284.9    
Epoxy | Europe                
Gross Margin [Abstract]                
Sales 102.3   93.4   202.7 195.2    
Epoxy | Other foreign                
Gross Margin [Abstract]                
Sales 123.0   97.0   226.6 182.8    
Winchester                
Gross Margin [Abstract]                
Sales 500.3   447.6   970.8 835.6    
Cost of goods sold 447.2   402.6   877.7 745.2    
Gross Profit 53.1   45.0   93.1 90.4    
Income (Loss) before Income Taxes [Abstract]                
Segment Reporting, Other Segment Item, Amount (25.0)   (20.0)   (49.8) (42.6)    
Restructuring charges 0.0   0.0   0.0 0.0    
Other Operating Income 0.0   0.0   0.0 0.0    
Interest Expense, Operating and Nonoperating 0.0   0.0   0.0 0.0    
Non-operating pension income 0.0   0.0   0.0 0.0    
Income (loss) before taxes 28.1   25.0   43.3 47.8    
Depreciation and amortization expense                
Depreciation and amortization 8.8   7.9   17.7 17.4    
Assets                
Assets 833.1   866.7   833.1 866.7 833.1  
Winchester | United States                
Gross Margin [Abstract]                
Sales 455.8   396.9   899.4 743.1    
Winchester | Europe                
Gross Margin [Abstract]                
Sales 29.6   20.4   41.5 33.0    
Winchester | Other foreign                
Gross Margin [Abstract]                
Sales 14.9   30.3   29.9 59.5    
Corporate/ other                
Gross Margin [Abstract]                
Sales 0.0   0.0   0.0 0.0    
Cost of goods sold 6.7   5.8   13.2 11.6    
Gross Profit (6.7)   (5.8)   (13.2) (11.6)    
Income (Loss) before Income Taxes [Abstract]                
Segment Reporting, Other Segment Item, Amount (24.3)   (18.9)   (56.2) (38.1)    
Restructuring charges (10.5)   (7.4)   (19.6) (11.4)    
Other Operating Income (0.1)   (0.2)   (0.1) (0.2)    
Interest Expense, Operating and Nonoperating 44.3   45.6   86.4 92.9    
Non-operating pension income 2.6   4.9   6.1 10.6    
Income (loss) before taxes (93.7)   (73.0)   (179.8) (143.6)    
Depreciation and amortization expense                
Depreciation and amortization 3.5   2.6   6.7 5.3    
Assets                
Assets 555.3   574.5   555.3 574.5 $ 555.3  
Corporate/ other | United States                
Gross Margin [Abstract]                
Sales 0.0   0.0   0.0 0.0    
Corporate/ other | Europe                
Gross Margin [Abstract]                
Sales 0.0   0.0   0.0 0.0    
Corporate/ other | Other foreign                
Gross Margin [Abstract]                
Sales $ 0.0   $ 0.0   $ 0.0 $ 0.0