v3.26.3
ACQUISITIONS (Details) - USD ($)
$ in Millions
9 Months Ended
Jun. 15, 2026
Apr. 18, 2025
Sep. 30, 2026
Sep. 30, 2025
Oct. 27, 2026
Dec. 31, 2025
Dec. 31, 2024
Asset Acquisition [Abstract]              
Payments to Acquire Businesses, Net of Cash Acquired     $ 0.0 $ 55.8      
Goodwill     $ 1,427.6 $ 1,425.9   $ 1,427.6 $ 1,423.6
$2,500.0 Million Secured Credit Facility              
Asset Acquisition [Abstract]              
OlinHuntsman Credit Facility         $ 2,500.0    
OlinHuntsman Term Loan              
Asset Acquisition [Abstract]              
Long-Term Debt, Gross         $ 750.0    
Quarterly Required Principal Payment Percent through Fiscal Quarter Including Fourth Anniversary of Close Date         1.25%    
Quarterly Required Principal Payment Percent through Maturity         1.875%    
$1,750.0 million OlinHuntsman Revolving Credit Facility              
Asset Acquisition [Abstract]              
Senior Revolving Credit Facility, Maximum Borrowing Capacity         $ 1,750.0    
AMMO, Inc.              
Asset Acquisition [Abstract]              
Payments to Acquire Businesses, Net of Cash Acquired   $ 55.8          
Goodwill   4.1          
Business Combination, Recognized Asset Acquired, Asset   62.2          
Business Combination, Recognized Liability Assumed, Liability   $ 6.4          
Hunstman Corporation [Member]              
Asset Acquisition [Abstract]              
Business Combination, Voting Equity Interest Acquired, Percentage 45.50%            
Conversion of Stock, Shares Issued 0.5476            
Olin Corporation [Member]              
Asset Acquisition [Abstract]              
Business Combination, Voting Equity Interest Acquired, Percentage 54.50%