v3.25.4
Cover
 12 Months Ended
Dec. 31, 2025
shares
Document Information [Line Items]  
Document type 20-F
Document registration statement false
Document annual report true
Document period end date Dec. 31, 2025
Current fiscal year end date --12-31
Document transition report false
Document shell company report false
Entity file number 001-35788
Entity registrant name ARCELORMITTAL
Entity incorporation, state or country code N4
Entity address, address line one 24-26, Boulevard d’Avranches
Entity address, postal zip code L-1160
Entity address, city or town Luxembourg
Entity address, country LU
Entity common stock, shares outstanding (in shares) 761,125,819
Entity well-known seasoned issuer Yes
Entity voluntary filers No
Entity current reporting status Yes
Entity interactive data current Yes
Entity filer category Large Accelerated Filer
Entity emerging growth company false
ICFR Auditor attestation flag true
Document Financial Statement Error Correction [Flag] false
Document accounting standard International Financial Reporting Standards
Entity shell company false
Entity central index key 0001243429
Document fiscal year focus 2025
Document fiscal period focus FY
Amendment flag false
New York Stock Exchange  
Document Information [Line Items]  
Title of 12(b) security Ordinary Shares
Trading symbol MT
Security exchange name NYSE
Business Contact  
Document Information [Line Items]  
Entity address, address line one 24-26, Boulevard d’Avranches
Entity address, postal zip code L-1160
Entity address, city or town Luxembourg
Entity address, country LU
Contact personnel name Henk Scheffer
Contact Personnel Email Address company.secretary@arcelormittal.com