v3.26.1
Provisions - Litigation and other matters - Non-tax-related proceedings Narrative (Details)
€ in Thousands, £ in Millions, zł in Millions
5 Months Ended 12 Months Ended 19 Months Ended
Jan. 09, 2026
Jul. 11, 2023
EUR (€)
Feb. 06, 2023
EUR (€)
Dec. 31, 2022
EUR (€)
Jan. 13, 2022
EUR (€)
Dec. 09, 2021
EUR (€)
Sep. 16, 2021
EUR (€)
May 29, 2020
May 16, 2021
EUR (€)
Dec. 31, 2025
EUR (€)
Dec. 31, 2025
GBP (£)
Dec. 31, 2025
PLN (zł)
Dec. 31, 2024
EUR (€)
judgement
Dec. 31, 1999
shares
Dec. 31, 1994
child
Dec. 31, 2022
EUR (€)
Dec. 31, 2025
GBP (£)
Dec. 31, 2025
PLN (zł)
Dec. 31, 2024
GBP (£)
judgement
Nov. 22, 2024
EUR (€)
Apr. 25, 2024
judgement
Dec. 31, 2023
EUR (€)
Jan. 23, 2019
Dec. 31, 2017
EUR (€)
Disclosure of other provisions [line items]                                                
PROVISIONS       € 8,149,000           € 8,355,000     € 8,407,000     € 8,149,000           € 8,441,000    
Banco Popular Espanol, S.A.                                                
Disclosure of other provisions [line items]                                                
Expected cost                                               € 680,000
Estimated cost of compensation to shareholders and bondholders applied to the commercial loyalty program                                               € 535,000
Santander Bank Polska S.A.                                                
Disclosure of other provisions [line items]                                                
Mortgage loans denominated in, or indexed to, CHF                   626,000               zł 2,642.0            
Santander Bank Polska S.A. | Agreement For The Sale Of Santander Bank Polska S.A.                                                
Disclosure of other provisions [line items]                                                
Sale of proportion of ownership interest in subsidiary 49.00%                                              
Santander Consumer Bank Polska                                                
Disclosure of other provisions [line items]                                                
Mortgage loans denominated in, or indexed to, CHF                   174,400               735.9            
Legal case to request court judgment on the validity of the swaps                                                
Disclosure of other provisions [line items]                                                
Arbitration matter, amount claimed by entity                   66,000                            
Arbitration matter, amount claimed by counterparty                   57,000                            
Arbitration matter, amount to be received by entity             € 66,000                                  
Arbitration matter, amount to be received by entity, interest             € 11,000                                  
"Planos Econmicos"                                                
Disclosure of other provisions [line items]                                                
Period of suspension of economic plan process               5 years                                
"Planos Econmicos" | Banco Santander (Brasil) S.A.                                                
Disclosure of other provisions [line items]                                                
PROVISIONS                   155,300                            
Banco Popular’s Compensation request                                                
Disclosure of other provisions [line items]                                                
Legal proceedings provision, possible loss, contingent liabilities                                       € 2,277,650        
Tax Dividend, Cum-ex Transactions                                                
Disclosure of other provisions [line items]                                                
PROVISIONS                   0                            
Individual plaintiff, CEO functions                                                
Disclosure of other provisions [line items]                                                
PROVISIONS                   35,500                            
Compensation sought in litigation claim                 € 112,000             61,900                
Losses on litigation settlements         € 51,400 € 67,800                                    
Decrease in losses on litigation settlements     € 8,000                                          
Gains on litigation settlements   € 9,600                                            
Individual plaintiff, CEO functions | 2018 variable remuneration                                                
Disclosure of other provisions [line items]                                                
Long-term metric achievement percentage       33.30%                                        
Conversion of active loans from swiss francs to PLN loans | Santander Bank Polska and Santander Consumer Bank Poland                                                
Disclosure of other provisions [line items]                                                
Mortgage loans, provision and adjustment to gross carrying amount                   1,391,900               5,874.3            
Mortgage loans, adjustment to gross carrying amount                   756,300               3,191.7            
Increase in adjustment to gross carrying amount, mortgage loans                   23,600   zł 99.7                        
Increase through other costs associated                   172,400   730.5                        
Conversion of active loans from swiss francs to PLN loans | Santander Bank Polska S.A.                                                
Disclosure of other provisions [line items]                                                
Mortgage loans, provision and adjustment to gross carrying amount                   1,129,400               4,766.4            
Conversion of active loans from swiss francs to PLN loans | Santander Consumer Bank Polska                                                
Disclosure of other provisions [line items]                                                
Mortgage loans, provision and adjustment to gross carrying amount                   262,500               1,107.9            
Inheritance trust | Banco Santander México, S.A., Institución de Banca Múltiple, Grupo Financiero Santander México                                                
Disclosure of other provisions [line items]                                                
Amount of sons involved in testamentary trust | child                             4                  
Amount of shares to be transferred by trustee (in shares) | shares                           36,700,000                    
Spanish supreme court, mortgage expenses                                                
Disclosure of other provisions [line items]                                                
Percentage of public notary expenses and agency expenses to be paid                                             50.00%  
Percentage of the registry expenses to be paid                                             100.00%  
Number of judgments rendered | judgement                         2           2   2      
Provision For Compensation And Associated Cost In Respect Of PPI Policies | Santander Insurance Services UK Limited                                                
Disclosure of other provisions [line items]                                                
PROVISIONS | £                                 £ 515.0              
Provision For Compensation And Associated Cost In Respect Of PPI Policies, Interest | Santander Insurance Services UK Limited                                                
Disclosure of other provisions [line items]                                                
PROVISIONS | £                                 162.0              
Other provisions                                                
Disclosure of other provisions [line items]                                                
PROVISIONS       € 4,073,000           4,993,000     € 5,051,000     € 4,073,000           4,634,000    
Other provisions | United Kingdom                                                
Disclosure of other provisions [line items]                                                
PROVISIONS                   736,000     654,000                 € 373,000    
Active loans, under IAS 37 | Conversion of active loans from swiss francs to PLN loans | Santander Bank Polska and Santander Consumer Bank Poland                                                
Disclosure of other provisions [line items]                                                
PROVISIONS                   635,600               zł 2,682.6            
Increase in existing provisions                   293,800   zł 1,245.3                        
Financial Conduct Authority (FCA) Review of The Vehicle Finance Market | Other provisions | United Kingdom                                                
Disclosure of other provisions [line items]                                                
PROVISIONS                   528,100     353,300       £ 461.0   £ 293.0          
Increase in existing provisions                   € 214,000 £ 183.0   € 353,000