v3.25.2
Financial liabilities - Narrative (Details)
€ in Millions, $ in Millions, $ in Millions
6 Months Ended
Mar. 06, 2025
EUR (€)
Feb. 17, 2025
EUR (€)
May 20, 2024
EUR (€)
Mar. 14, 2024
EUR (€)
Jan. 22, 2024
EUR (€)
Jun. 30, 2025
EUR (€)
Jun. 30, 2024
EUR (€)
Mar. 29, 2025
EUR (€)
Mar. 19, 2025
EUR (€)
Mar. 18, 2025
EUR (€)
Mar. 06, 2025
AUD ($)
Feb. 06, 2025
EUR (€)
Dec. 31, 2024
EUR (€)
Mar. 14, 2024
USD ($)
Feb. 08, 2024
EUR (€)
Feb. 08, 2024
USD ($)
Disclosure of financial liabilities [line items]                                
Subordinated liabilities           € 4,084.0 € 3,210.0                  
Other financial liabilities           € 44,297.0             € 39,916.0      
Subordinated | Issuance By Banco Santander SA In January 2024                                
Disclosure of financial liabilities [line items]                                
Notional amount         € 1,250.0                      
Subordinated issue, term         10 years 3 months                      
Notional amount, placed on the market (in percentage)         99.74%                      
Interest rate         5.00%                      
Initial interest rate term         5 years 3 months                      
Adjustment to reference rate, after initial interest rate period         2.50%                      
Subordinated issue, Euro Swap rate term         5 years                      
Subordinated Liabilities, Preference Shares                                
Disclosure of financial liabilities [line items]                                
Notional amount     € 187.6                          
Issuance By Banco Santander S.A. In March 2025 | Subordinated                                
Disclosure of financial liabilities [line items]                                
Notional amount € 202.0             € 50.0   € 1,500.0 $ 350          
Subordinated issue, term 10 years                              
Notional amount, placed on the market (in percentage) 100.00%                   100.00%          
Interest rate 1.92%                   1.92%          
Initial interest rate term 5 years                              
Issuance By Banco Santander S.A. In March 2025 | Subordinated Debentures                                
Disclosure of financial liabilities [line items]                                
Notional amount € 144.0                   $ 250          
Subordinated issue, term 10 years                              
Notional amount, placed on the market (in percentage) 100.00%                   100.00%          
Interest rate 5.80%                   5.80%          
Initial interest rate term 5 years                              
Adjustment to reference rate, after initial interest rate period 1.92%                   1.92%          
Repaid By Banco Santander S.A. In March 2025 | Tier One Contingently Convertible Preferred Securities                                
Disclosure of financial liabilities [line items]                                
Notional amount                 € 187.6              
Issuance By Banco Santander S.A. In February 2025, ISIN XS138406464587 | Subordinated                                
Disclosure of financial liabilities [line items]                                
Notional amount                       € 1,500.0        
Subordinated liabilities   € 600.8                            
Issuance By Banco Santander S.A. In February 2025, ISIN XS1548444816 | Subordinated                                
Disclosure of financial liabilities [line items]                                
Notional amount                       € 1,000.0        
Subordinated liabilities   € 563.6                            
Issuance By Banco Santander S.A. In March 2024 | Subordinated                                
Disclosure of financial liabilities [line items]                                
Notional amount       € 1,158.0                   $ 1,250    
Subordinated issue, term       10 years                        
Interest rate       6.35%                   6.35%    
Repaid By Banco Santander S.A. In February 2024 | Tier One Contingently Convertible Preferred Securities                                
Disclosure of financial liabilities [line items]                                
Notional amount                             € 1,110.0 $ 1,200
Repaid By Banco Santander S.A. In May 2024 | Subordinated Liabilities, Preference Shares                                
Disclosure of financial liabilities [line items]                                
Notional amount     1,312.4                          
Issuance By Banco Santander S.A. In May 2024 | Subordinated Liabilities, Preference Shares                                
Disclosure of financial liabilities [line items]                                
Notional amount     € 1,500.0                          
Interest rate     7.00%                          
Initial interest rate term     6 years                          
Reprice term     5 years                          
Subordinated issue, mid-swap rate term     5 years                          
Issuance By Banco Santander S.A. In May 2024 | Subordinated Liabilities, Preference Shares | Mid Swap Rate Five Year Euro                                
Disclosure of financial liabilities [line items]                                
Adjustment to reference rate, after initial interest rate period     4.432%