v3.25.4
PROVISIONS, CONTINGENCIES AND COMMITMENTS - Commitments - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 20, 2022
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
tonne
Dec. 26, 2025
Aug. 01, 2025
Disclosure of transactions between related parties [line items]          
Period of nuclear power contract (in years)       18 years  
Increase in commitments related to raw materials and energy   $ 5,600      
Commitments in relation to associates   441 $ 1,704    
Commitments in relation to joint ventures   681 719    
Provision of guarantees or collateral to entity, third party transactions   299 256    
Contractual commitments to sell   $ 2,717 2,897    
Offtake agreement, period   25 years      
AML          
Disclosure of transactions between related parties [line items]          
Contractual capital commitments   $ 108 $ 257    
Concentrate sinter fines capacity (in tonnes) | tonne     20,000,000    
ArcelorMittal Brasil S.A.          
Disclosure of transactions between related parties [line items]          
Other commitments, industrial capital expenditure   $ 535 $ 295    
5.146 billion term loan, due 2030          
Disclosure of transactions between related parties [line items]          
Guarantees (in percent)   60.00%      
Asset-Based Revolving Credit Facility | Operating Subsidiaries | South Africa          
Disclosure of transactions between related parties [line items]          
Inventory pledged in asset-based revolving credit facility   $ 175      
Debt instrument, ceded bank accounts to secure environmental obligations, true sale of receivables programs and the revolving base finance facility   43      
Total for all associates          
Disclosure of transactions between related parties [line items]          
Provision of guarantees or collateral by entity, related party transactions   0 11    
Commitments within sureties, guarantees, LOC, pledges, and other collateral   250 291    
Total for all joint ventures          
Disclosure of transactions between related parties [line items]          
Provision of guarantees or collateral by entity, related party transactions   5,380 6,259    
Enerfos          
Disclosure of transactions between related parties [line items]          
Commitments in relation to joint ventures   378 380    
VdSA          
Disclosure of transactions between related parties [line items]          
Commitments in relation to joint ventures   1,944      
VdSA | Total for all joint ventures          
Disclosure of transactions between related parties [line items]          
Provision of guarantees or collateral by entity, related party transactions   414 183    
Global Chartering          
Disclosure of transactions between related parties [line items]          
Commitments within sureties, guarantees, LOC, pledges, and other collateral, related to lease obligations   248 303    
AMNS India          
Disclosure of transactions between related parties [line items]          
Contractual capital commitments   7,700      
Contractual commitments to sell   2,655 2,787    
AMNS India | Total for all joint ventures          
Disclosure of transactions between related parties [line items]          
Provision of guarantees or collateral by entity, related party transactions   4,400 4,038    
Tameh          
Disclosure of transactions between related parties [line items]          
Commitments in relation to joint ventures   $ 245 287    
Kryvyi Rih industrial gas          
Disclosure of transactions between related parties [line items]          
Commitments in relation to associates     $ 798    
The Fonds d'Urbanisation et d'Aménagement du Plateau de Kirchberg and the State of the Grand-Duchy of Luxembourg | ArcelorMittal          
Disclosure of transactions between related parties [line items]          
Proportion of ownership interest in subsidiary (in percent) 50.00%        
Aperam          
Disclosure of transactions between related parties [line items]          
Percentage of voting equity interests acquired         5.40%