v3.25.4
SCOPE OF CONSOLIDATION - List of Subsidiaries (Details)
 12 Months Ended
Jul. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
ArcelorMittal Brasil S.A. | Votorantim S.A      
Disclosure of subsidiaries [line items]      
Proportion of ownership interests held by non-controlling interests (in percent) 2.92%    
ArcelorMittal Dofasco G.P. | North America      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal México S.A. de C.V. | North America      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Long Products Canada G.P. | North America      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Calvert LLC | North America      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Texas HBI LLC      
Disclosure of subsidiaries [line items]      
Proportion of ownership interests held by non-controlling interests (in percent)   20.00% 20.00%
ArcelorMittal Texas HBI LLC | North America      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   80.00%  
ArcelorMittal Brasil S.A. | Brazil and neighboring countries ("Brazil")      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
Acindar Industria Argentina de Aceros S.A. | Brazil and neighboring countries ("Brazil")      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Pecém | Brazil and neighboring countries ("Brazil")      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal France S.A.S. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Belgium N.V. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal España S.A. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   99.85%  
ArcelorMittal Flat Europe S.A. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Poland S.A. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Eisenhüttenstadt GmbH | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Bremen GmbH | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Méditerranée S.A.S. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Belval & Differdange S.A. | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Hamburg GmbH | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal Duisburg GmbH | Europe      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
ArcelorMittal International Luxembourg S.A. | Sustainable Solutions      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   100.00%  
AM Green Energy India Private Limited      
Disclosure of subsidiaries [line items]      
Right to variable returns (in percent)   1  
AM Green Energy India Private Limited | Sustainable Solutions      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   74.00%  
ArcelorMittal Mining Canada G.P. and ArcelorMittal Infrastructure Canada G.P. ("AMMC")      
Disclosure of subsidiaries [line items]      
Proportion of ownership interests held by non-controlling interests (in percent)   15.00% 15.00%
ArcelorMittal Mining Canada G.P. and ArcelorMittal Infrastructure Canada G.P. ("AMMC") | Mining      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   85.00%  
ArcelorMittal Liberia Ltd      
Disclosure of subsidiaries [line items]      
Proportion of ownership interests held by non-controlling interests (in percent)   15.00% 15.00%
ArcelorMittal Liberia Ltd | Mining      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   85.00%  
ArcelorMittal South Africa Ltd. ("AMSA")      
Disclosure of subsidiaries [line items]      
Proportion of voting rights held in subsidiary   53.05%  
Proportion of ownership interests held by non-controlling interests (in percent)   30.78% 30.78%
ArcelorMittal South Africa Ltd. ("AMSA") | Others      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   69.22%  
PJSC ArcelorMittal Kryvyi Rih ("AMKR")      
Disclosure of subsidiaries [line items]      
Proportion of ownership interests held by non-controlling interests (in percent)   4.87% 4.87%
PJSC ArcelorMittal Kryvyi Rih ("AMKR") | Others      
Disclosure of subsidiaries [line items]      
Proportion of ownership interest in subsidiary (in percent)   95.13%