v3.26.1
Financial liabilities - Schedule of financial liabilities measured at other than fair value (Details) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of financial liabilities [line items]    
Financial liabilities, at fair value € 1,496 € 1,110
Debt instruments    
Disclosure of financial liabilities [line items]    
Financial liabilities 348,067 324,390
Carrying amount    
Disclosure of financial liabilities [line items]    
Financial liabilities 1,494,058 1,385,088
Carrying amount | Deposits    
Disclosure of financial liabilities [line items]    
Financial liabilities 1,161,212 1,072,384
Carrying amount | Debt instruments    
Disclosure of financial liabilities [line items]    
Financial liabilities 332,846 312,704
Fair  value    
Disclosure of financial liabilities [line items]    
Financial liabilities, at fair value 1,495,464 1,387,320
Fair  value | Deposits    
Disclosure of financial liabilities [line items]    
Financial liabilities, at fair value 1,161,811 1,073,147
Fair  value | Debt instruments    
Disclosure of financial liabilities [line items]    
Financial liabilities, at fair value € 333,653 € 314,173