v3.26.1
II. ACCOUNTING POLICIES (Details Textual 2) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of associates [line items]      
Proportion of ownership interest in subsidiary 50.00%    
Number of outstanding shares 1,011,823,958 1,084,272,191 1,167,888,739
Ternium S.A. [member]      
Disclosure of associates [line items]      
Proportion of ownership interest in subsidiary 11.46%    
Usiminas [member]      
Disclosure of associates [line items]      
Proportion of ownership interest in subsidiary 3.96%    
Proportion Of Shares Or Voting Rights In Subsidiary 6.76%    
Treasury shares [member]      
Disclosure of associates [line items]      
Number of outstanding shares 60,170,972 78,485,337 12,648,091
Italy      
Disclosure of associates [line items]      
Net defined benefit liability (asset) at end of period $ 10.7    
USA      
Disclosure of associates [line items]      
Net defined contribution plan liability (asset) at end of period 0.6    
Unfunded defined benefit employee retirement plan for certain senior officers [member]      
Disclosure of associates [line items]      
Net defined benefit liability (asset) at end of period $ 63.4    
Techgen S.A. [member] | Ternium S.A. [member]      
Disclosure of associates [line items]      
Proportion of ownership interest in subsidiary 48.00%    
Techgen S.A. [member] | Tecpetrol International S.A. [member]      
Disclosure of associates [line items]      
Proportion of ownership interest in subsidiary 30.00%    
Techgen S.A. [member] | Tenaris [member]      
Disclosure of associates [line items]      
Proportion of ownership interest in subsidiary 22.00%