v3.26.1
Subordinated liabilities - Schedule of subordinated liabilities detail, by currency of issue (Details) - Financial liabilities at amortised cost
€ in Millions, £ in Millions, R$ in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2025
EUR (€)
Dec. 31, 2025
USD ($)
Dec. 31, 2025
BRL (R$)
Dec. 31, 2025
GBP (£)
Dec. 31, 2024
EUR (€)
Dec. 31, 2023
EUR (€)
Dec. 31, 2022
EUR (€)
Measurement of financial assets and liabilities and recognition of fair value changes              
Outstanding issue amount € 29,287       € 35,813 € 30,912 € 25,926
Euro              
Measurement of financial assets and liabilities and recognition of fair value changes              
Outstanding issue amount € 11,402       14,999 13,684  
Annual interest rate 4.55%            
US dollar              
Measurement of financial assets and liabilities and recognition of fair value changes              
Outstanding issue amount € 9,750 $ 11,462     13,425 11,300  
Annual interest rate 6.53%            
Brazilian real              
Measurement of financial assets and liabilities and recognition of fair value changes              
Outstanding issue amount € 4,354   R$ 28,117   3,600 2,518  
Annual interest rate 16.30%            
Pound sterling              
Measurement of financial assets and liabilities and recognition of fair value changes              
Outstanding issue amount € 1,347     £ 1,176 1,409 1,353  
Annual interest rate 4.28%            
Other currencies              
Measurement of financial assets and liabilities and recognition of fair value changes              
Outstanding issue amount € 2,434       € 2,380 € 2,057