v3.26.1
Grupo Santander - Accelerated placement of ordinary shares of Santander Bank Polska (Details)
€ / shares in Units, zł / shares in Units, € in Millions, zł in Millions
Dec. 31, 2025
€ / shares
Dec. 02, 2025
shares
Sep. 13, 2024
PLN (zł)
Sep. 13, 2024
EUR (€)
Sep. 10, 2024
zł / shares
shares
Sep. 09, 2024
Dec. 31, 2024
€ / shares
Sep. 10, 2024
€ / shares
Dec. 31, 2023
€ / shares
Dec. 31, 2022
€ / shares
Disclosure of detailed information about business combination [line items]                    
Nominal value per share (in euro per share) | € / shares € 0.50           € 0.50   € 0.50 € 0.50
Santander Bank Polska S.A.                    
Disclosure of detailed information about business combination [line items]                    
Sale of ordinary shares in subsidiary (in shares) | shares   3,576,626     5,320,000          
Percentage of share capital   3.50%     5.20%     5.20%    
Proceeds from changes in ownership interests in subsidiaries that do not result in loss of control     zł 2,463 € 575            
Ownership interest in subsidiary 58.70%   62.20% 62.20%   67.40%        
Santander Bank Polska S.A. | Other reserves                    
Disclosure of detailed information about business combination [line items]                    
Increase (decrease) through change in equity of subsidiaries, equity       € 158            
Santander Bank Polska S.A. | Other comprehensive income                    
Disclosure of detailed information about business combination [line items]                    
Increase (decrease) through change in equity of subsidiaries, equity       57            
Santander Bank Polska S.A. | Non-controlling interest, other elements                    
Disclosure of detailed information about business combination [line items]                    
Increase (decrease) through change in equity of subsidiaries, equity       € 360            
Santander Bank Polska S.A. | Ordinary shares                    
Disclosure of detailed information about business combination [line items]                    
Nominal value per share (in euro per share) | (per share)         zł 463     € 108