v3.26.1
CONTINGENCIES, COMMITMENTS AND RESTRICTIONS ON THE DISTRIBUTION OF PROFITS (Commitments: a-l) (Details)
MMBTU in Thousands, m³ in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2025
USD ($)
m³
May 09, 2018
MMBTU
Apr. 24, 2017
MW
Dec. 31, 2025
USD ($)
MMBTU
m³
Dec. 30, 2019
Techgen S.A. de C.V. | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Guarantor obligations, outstanding $ 57.2     $ 57.2  
Iron Ore, Pellets and Iron Ore Fines | Vale S.A. and LHG Mining | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, minimum percentage of volume required       80.00%  
Long-term purchase commitment, amount 259.0     $ 259.0  
Iron Ore, Pellets and Iron Ore Fines | Vale S.A. and LHG Mining | Scenario one | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, minimum percentage of volume required       80.00%  
Long-term purchase commitment, percentage of penalty       7.00%  
Iron Ore, Pellets and Iron Ore Fines | Vale S.A. and LHG Mining | Scenario one | Bottom of range | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, percentage of total volume actually operated       70.00%  
Iron Ore, Pellets and Iron Ore Fines | Vale S.A. and LHG Mining | Scenario one | Top of range | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, percentage of total volume actually operated       75.00%  
Iron Ore, Pellets and Iron Ore Fines | Vale S.A. and LHG Mining | Scenario two | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, minimum percentage of volume required       80.00%  
Long-term purchase commitment, percentage of penalty       15.00%  
Iron Ore, Pellets and Iron Ore Fines | Vale S.A. and LHG Mining | Scenario two | Bottom of range | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, percentage of total volume actually operated       70.00%  
Natural Gas | Tecpetrol | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount 46.3     $ 46.3  
Natural Gas | Transportadora de Gas del Norte S.A. and Energy Consulting Services S.A. | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount 16.8     16.8  
Natural Gas | Gas Industrial de Monterrey, S.A. de C.V. | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount 21.6     21.6  
Guarantor obligations, amount 28.8     28.8  
Long-term purchase commitment, obligations outstanding 9.5     9.5  
Industrial Gas | Air Liquide Argentina S.A. | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount $ 52.0     $ 52.0  
Industrial Gas | Praxair Mexico | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment , minimum annual consumption, volume | m³ 96     96  
Long-term purchase commitment , minimum annual consumption, amount $ 4.5     $ 4.5  
Property, plant and equipment | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount 18.0     18.0  
Property, plant and equipment | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount 535.4     535.4  
Wind Generation Farm | Ternium Argentina          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, amount 53.3     53.3  
Electric Power | Techgen S.A. de C.V. | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, term     25 years    
Long-term purchase commitment, electrical demand | MW     699    
Percentage of electricity capacity supplied     78.00%    
Natural Gas Transportation | Kinder Morgan Texas Pipeline L.L.C., Kinder Morgan Tejas Pipeline L.L.C. and Kinder Morgan Border Pipeline L.L.C. | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, term   10 years      
Long-term purchase commitment, contracted daily capacity | MMBTU   60      
Long-term purchase commitment, annual cost 3.7     $ 3.7  
Natural Gas Transportation | Kinder Morgan Texas Pipeline L.L.C., Kinder Morgan Tejas Pipeline L.L.C. and Kinder Morgan Gas Natural de México S. de R.L. de C.V. | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, term         15 years
Long-term purchase commitment, contracted daily capacity | MMBTU       31  
Long-term purchase commitment, annual cost 4.8     $ 4.8  
Natural Gas Transportation | Kinder Morgan Gas Natural de Mexico, S. de R.L. de C.V., Kinder Morgan Texas Pipeline LLC, Kinder Morgan Tejas Pipeline LLC | Ternium Mexico          
Disclosure of contingent liabilities [line items]          
Guarantor obligations, outstanding $ 72.2     72.2  
Guarantor obligations, percentage 48.00%        
Natural Gas Transportation | Kinder Morgan Gas Natural de Mexico, S. de R.L. de C.V., Kinder Morgan Texas Pipeline LLC, Kinder Morgan Tejas Pipeline LLC | Techgen          
Disclosure of contingent liabilities [line items]          
Long-term purchase commitment, obligations outstanding $ 150.4     $ 150.4