v3.26.1
Restructuring - Summary of Pre-tax Charges, Restructuring Activities (Details)
$ in Millions
Jun. 30, 2026
USD ($)
Minimum | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected $ 233.0
Minimum | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 50.0
Minimum | Cash Restructuring Costs  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 79.0
Minimum | Severance and employee benefits | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 5.0
Minimum | Severance and employee benefits | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 1.0
Minimum | Plant cleaning, waste disposal and demolition costs | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 52.0
Minimum | Plant cleaning, waste disposal and demolition costs | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 21.0
Minimum | Noncash Restructuring Costs  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 204.0
Minimum | Impairment, Depreciation and Asset Disposal Costs | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 176.0
Minimum | Depreciation and asset disposal costs | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 28.0
Maximum | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 252.0
Maximum | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 54.0
Maximum | Cash Restructuring Costs  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 93.0
Maximum | Severance and employee benefits | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 5.0
Maximum | Severance and employee benefits | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 1.0
Maximum | Plant cleaning, waste disposal and demolition costs | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 62.0
Maximum | Plant cleaning, waste disposal and demolition costs | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 25.0
Maximum | Noncash Restructuring Costs  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 213.0
Maximum | Impairment, Depreciation and Asset Disposal Costs | Stickney Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected 185.0
Maximum | Depreciation and asset disposal costs | Phthalic Anhydride Shutdown  
Restructuring Cost and Reserve [Line Items]  
Cumulative restructuring charges, expected $ 28.0