v3.25.2
Fair value of assets and liabilities - Sensitivity analysis of level 3 instruments (Details) - Level 3 - EUR (€)
€ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Disclosure of fair value measurement of assets [line items]    
Positive fair value movements from using reasonable possible alternatives € 37 € 28
Negative fair value movements from using reasonable possible alternatives (28) (47)
Financial assets at fair value through profit or loss, category | Equity (equity derivatives, structured notes)    
Disclosure of fair value measurement of assets [line items]    
Positive fair value movements from using reasonable possible alternatives 19 21
Negative fair value movements from using reasonable possible alternatives (9) (20)
Financial assets at fair value through profit or loss, category | Interest rates (Rates derivatives, FX derivatives)    
Disclosure of fair value measurement of assets [line items]    
Positive fair value movements from using reasonable possible alternatives 1 5
Negative fair value movements from using reasonable possible alternatives 0 0
Financial assets at fair value through profit or loss, category | Credit (Debt securities, Loans, structured notes, credit derivatives)    
Disclosure of fair value measurement of assets [line items]    
Positive fair value movements from using reasonable possible alternatives 15 2
Negative fair value movements from using reasonable possible alternatives (19) (27)
Financial assets at FVOCI | Equity securities    
Disclosure of fair value measurement of assets [line items]    
Positive fair value movements from using reasonable possible alternatives 2 0
Negative fair value movements from using reasonable possible alternatives € 0 € 0