v3.26.1
Introduction, basis of presentation of the interim condensed consolidated financial statements and other information - Comparative information (Details) - EUR (€)
€ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Disclosure of initial application of standards or interpretations [line items]      
Profit/(loss) for the period € 9,414 € 7,463  
Provisions 9,211   € 8,355
Other operating expenses 1,305 1,196  
Other provisions      
Disclosure of initial application of standards or interpretations [line items]      
Provisions € 2,492   € 2,004
Increase (Decrease) Due To Changes In Presentation      
Disclosure of initial application of standards or interpretations [line items]      
Profit/(loss) for the period   238  
Other operating expenses   204  
Increase (Decrease) Due To Changes In Presentation | Other provisions      
Disclosure of initial application of standards or interpretations [line items]      
Provisions   € (204)  
Mexico, Pesos      
Disclosure of initial application of standards or interpretations [line items]      
Change in foreign currency exchange rate (as a percent) 5.81%    
Change in average foreign currency exchange rate (as a percent) 7.02%    
United States of America, Dollars      
Disclosure of initial application of standards or interpretations [line items]      
Change in foreign currency exchange rate (as a percent) 2.88%    
Change in average foreign currency exchange rate (as a percent) (5.45%)    
Brazil, Brazil Real      
Disclosure of initial application of standards or interpretations [line items]      
Change in foreign currency exchange rate (as a percent) 9.18%    
Change in average foreign currency exchange rate (as a percent) 5.09%    
Argentina, Pesos      
Disclosure of initial application of standards or interpretations [line items]      
Change in foreign currency exchange rate (as a percent) 0.80%    
United Kingdom, Pounds      
Disclosure of initial application of standards or interpretations [line items]      
Change in foreign currency exchange rate (as a percent) 1.39%    
Change in average foreign currency exchange rate (as a percent) (2.47%)    
Chile, Pesos      
Disclosure of initial application of standards or interpretations [line items]      
Change in foreign currency exchange rate (as a percent) 0.63%    
Change in average foreign currency exchange rate (as a percent) 1.11%