v3.26.1
Note 31 - Related party transactions (Details Textual) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Dec. 17, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Sep. 17, 2025
May 06, 2025
Disclosure of transactions between related parties [line items]              
Total number of shares issued (in shares)   1,071,994,930 1,071,994,930 1,162,757,528 1,180,536,830   1,162,757,528
Key management personnel compensation, short-term employee benefits     $ 44.7 $ 33.4 $ 47.5    
Key management personnel compensation, other long-term employee benefits     $ 6.7 $ 6.9 $ 5.6    
Techint Holdings S.àr.l. [Member] | Bottom of range [member]              
Disclosure of transactions between related parties [line items]              
Proportion of ownership interest in associate           67.00%  
San Faustin S.A. [member]              
Disclosure of transactions between related parties [line items]              
Percent of company voting capital   70.07% 70.07%        
Total number of shares issued (in shares)   708,945,896 708,945,896        
Proportion of ownership interest in associate   66.13% 66.13%        
Techint Holdings S.àr.l. [Member] | Tenaris SA [member]              
Disclosure of transactions between related parties [line items]              
Number of ordinary shares sale   4,819,291          
Number of ordinary shares sale settled   4,659,291          
Shares disposal program number of ordinary shares sale 2,600,000            
Techint Holdings S.àr.l. [Member] | Tenaris SA [member] | Top of range [member] | Major ordinary share transactions [member]              
Disclosure of transactions between related parties [line items]              
Shares disposal program number of ordinary shares sale 21,000,000            
Key management personnel of entity or parent [member]              
Disclosure of transactions between related parties [line items]              
Percent of company voting capital   0.09% 0.09%        
Proportion of ownership interest in associate   0.08% 0.08%        
Units issued, related party transactions (in shares)     408,000 448,000 388,000