v3.25.4
SCOPE OF CONSOLIDATION - Other Investments Narrative (Details) - Other investments - USD ($)
$ in Millions
12 Months Ended 46 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2024
ArcelorMittal XCarb®      
Disclosure of financial assets [line items]      
Payments for acquisition $ 19 $ 11 $ 219
Unrealized gains (losses) recognized in other comprehensive income 3 13  
ArcelorMittal XCarb® | Maximum      
Disclosure of financial assets [line items]      
Annual investment commitment 100    
Stalprodukt S.A.      
Disclosure of financial assets [line items]      
Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax $ 2 $ 3