v3.25.3
SEGMENT INFORMATION (Details 1) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended 52 Months Ended
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Sep. 30, 2025
Sep. 30, 2024
Jun. 30, 2025
Dec. 31, 2024
Gross Margin [Abstract]                    
Sales $ 1,713.2     $ 1,589.5     $ 5,115.7 $ 4,868.8    
Cost of goods sold 1,529.8     1,455.0     4,645.5 4,289.2    
Gross Profit 183.4     134.5     470.2 579.6    
Income (Loss) before Income Taxes [Abstract]                    
Segment Reporting, Other Segment Item, Amount (99.1)     (111.7)     (296.7) (308.2)    
Restructuring charges (2.9) $ (7.4) $ (4.0) (7.9) $ (6.8) $ (8.3) (14.3) (23.0) $ (240.7)  
Other Operating Income 0.4     0.6     0.2 0.8    
Interest Expense, Operating and Nonoperating (46.8)     (48.4)     (142.1) (139.6)    
Interest income 1.6     1.0     4.0 2.7    
Non-operating pension income 4.9     6.7     15.5 19.4    
Income (loss) before taxes 41.5     (25.2)     36.8 131.7    
Depreciation and amortization expense                    
Depreciation and amortization 133.8     130.2     395.9 388.9    
Assets                    
Assets 7,600.9     7,518.3     7,600.9 7,518.3   $ 7,579.1
United States                    
Gross Margin [Abstract]                    
Sales 1,136.1     1,130.0     3,475.2 3,508.4    
Europe                    
Gross Margin [Abstract]                    
Sales 159.3     145.8     462.7 438.3    
Other foreign                    
Gross Margin [Abstract]                    
Sales 417.8     313.7     1,177.8 922.1    
Chlor Alkali Products and Vinyls                    
Gross Margin [Abstract]                    
Sales 924.0     871.6     2,828.0 2,676.5    
Cost of goods sold 758.0     778.7     2,431.8 2,323.2    
Gross Profit 166.0     92.9     396.2 353.3    
Income (Loss) before Income Taxes [Abstract]                    
Segment Reporting, Other Segment Item, Amount (38.4)     (47.6)     (125.4) (132.1)    
Restructuring charges 0.0     0.0     0.0 0.0 (128.9)  
Other Operating Income 0.0           0.0 0.0    
Interest Expense, Operating and Nonoperating 0.0     0.0     0.0 0.0    
Interest income 0.0     0.0     0.0 0.0    
Non-operating pension income 0.0     0.0     0.0 0.0    
Income (loss) before taxes 127.6     45.3     270.8 221.2    
Depreciation and amortization expense                    
Depreciation and amortization 109.0     106.5     322.5 319.1    
Assets                    
Assets 5,203.8     5,307.7     5,203.8 5,307.7    
Chlor Alkali Products and Vinyls | United States                    
Gross Margin [Abstract]                    
Sales 624.7     616.9     1,935.8 1,924.0    
Chlor Alkali Products and Vinyls | Europe                    
Gross Margin [Abstract]                    
Sales 48.4     48.5     123.6 129.3    
Chlor Alkali Products and Vinyls | Other foreign                    
Gross Margin [Abstract]                    
Sales 250.9     206.2     768.6 623.2    
Epoxy                    
Gross Margin [Abstract]                    
Sales 349.6     285.1     1,012.5 944.1    
Cost of goods sold 367.4     313.2     1,052.5 959.9    
Gross Profit (17.8)     (28.1)     (40.0) (15.8)    
Income (Loss) before Income Taxes [Abstract]                    
Segment Reporting, Other Segment Item, Amount (14.4)     (14.7)     (44.3) (41.8)    
Restructuring charges 0.0     0.0     0.0 0.0 $ (111.8)  
Other Operating Income 0.0           0.0 0.0    
Interest Expense, Operating and Nonoperating 0.0     0.0     0.0 0.0    
Interest income 0.0     0.0     0.0 0.0    
Non-operating pension income 0.0     0.0     0.0 0.0    
Income (loss) before taxes (32.2)     (42.8)     (84.3) (57.6)    
Depreciation and amortization expense                    
Depreciation and amortization 13.2     13.7     39.1 40.6    
Assets                    
Assets 923.8     924.5     923.8 924.5    
Epoxy | United States                    
Gross Margin [Abstract]                    
Sales 139.5     136.2     424.4 474.3    
Epoxy | Europe                    
Gross Margin [Abstract]                    
Sales 88.1     75.1     283.3 239.3    
Epoxy | Other foreign                    
Gross Margin [Abstract]                    
Sales 122.0     73.8     304.8 230.5    
Winchester                    
Gross Margin [Abstract]                    
Sales 439.6     432.8     1,275.2 1,248.2    
Cost of goods sold 398.5     356.8     1,143.7 985.9    
Gross Profit 41.1     76.0     131.5 262.3    
Income (Loss) before Income Taxes [Abstract]                    
Segment Reporting, Other Segment Item, Amount (21.8)     (22.6)     (64.4) (66.4)    
Restructuring charges 0.0     0.0     0.0 0.0    
Other Operating Income 0.0           0.0 0.0    
Interest Expense, Operating and Nonoperating 0.0     0.0     0.0 0.0    
Interest income 0.0     0.0     0.0 0.0    
Non-operating pension income 0.0     0.0     0.0 0.0    
Income (loss) before taxes 19.3     53.4     67.1 195.9    
Depreciation and amortization expense                    
Depreciation and amortization 7.8     8.5     25.2 24.7    
Assets                    
Assets 924.5     797.5     924.5 797.5    
Winchester | United States                    
Gross Margin [Abstract]                    
Sales 371.9     376.9     1,115.0 1,110.1    
Winchester | Europe                    
Gross Margin [Abstract]                    
Sales 22.8     22.2     55.8 69.7    
Winchester | Other foreign                    
Gross Margin [Abstract]                    
Sales 44.9     33.7     104.4 68.4    
Corporate/ other                    
Gross Margin [Abstract]                    
Sales 0.0     0.0     0.0 0.0    
Cost of goods sold 5.9     6.3     17.5 20.2    
Gross Profit (5.9)     (6.3)     (17.5) (20.2)    
Income (Loss) before Income Taxes [Abstract]                    
Segment Reporting, Other Segment Item, Amount (24.5)     (26.8)     (62.6) (67.9)    
Restructuring charges (2.9)     (7.9)     (14.3) (23.0)    
Other Operating Income 0.4     0.6     0.2 0.8    
Interest Expense, Operating and Nonoperating 46.8     48.4     142.1 139.6    
Interest income 1.6     1.0     4.0 2.7    
Non-operating pension income 4.9     6.7     15.5 19.4    
Income (loss) before taxes (73.2)     (81.1)     (216.8) (227.8)    
Depreciation and amortization expense                    
Depreciation and amortization 3.8     1.5     9.1 4.5    
Assets                    
Assets 548.8     488.6     548.8 488.6    
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