v3.25.4
Derivatives and hedge accounting - Additional information (Details)
 12 Months Ended
Dec. 31, 2025
EUR (€)
Dec. 31, 2024
EUR (€)
-  fair value hedges | Euro    
Net Interest Income at Risk [Line Items]    
Average rate of hedging instrument 2.16% 2.08%
-  fair value hedges | US Dollar    
Net Interest Income at Risk [Line Items]    
Average rate of hedging instrument 4.43% 4.22%
-  fair value hedges | Financial liabilities at fair value through profit or loss    
Net Interest Income at Risk [Line Items]    
Derivative financial liabilities held for hedging € 54,000,000 € 79,000,000
Cash flow hedges | Euro | Average | – Interest rate swaps    
Net Interest Income at Risk [Line Items]    
Fixed interest rate 1.81% 1.79%
Cash flow hedges | US Dollar | – Cross currency swaps    
Net Interest Income at Risk [Line Items]    
Average foreign exchange rate 0.97 1.03
Cash flow hedges | US Dollar | Average | – Interest rate swaps    
Net Interest Income at Risk [Line Items]    
Fixed interest rate 3.85% 3.99%
Cash flow hedges | Polish Zloty | Average | – Interest rate swaps    
Net Interest Income at Risk [Line Items]    
Fixed interest rate 4.27% 4.37%
Cash flow hedges | Australian Dollar | – Cross currency swaps    
Net Interest Income at Risk [Line Items]    
Average foreign exchange rate 1.56 1.52
Cash flow hedges | Australian Dollar | Average | – Interest rate swaps    
Net Interest Income at Risk [Line Items]    
Fixed interest rate 3.38% 3.29%
Cash flow hedges | Financial liabilities at fair value through profit or loss    
Net Interest Income at Risk [Line Items]    
Derivative financial liabilities held for hedging € 254,000,000 € 573,000,000
-  hedges of net investments in foreign operations | US Dollar    
Net Interest Income at Risk [Line Items]    
Average foreign exchange rate 1.12 1.08
-  hedges of net investments in foreign operations | Polish Zloty    
Net Interest Income at Risk [Line Items]    
Average foreign exchange rate 4.24 4.31
-  hedges of net investments in foreign operations | Australian Dollar    
Net Interest Income at Risk [Line Items]    
Average foreign exchange rate 1.75 1.64
-  hedges of net investments in foreign operations | Thai Baht    
Net Interest Income at Risk [Line Items]    
Average foreign exchange rate 36.98 38.00
-  hedges of net investments in foreign operations | Financial liabilities at fair value through profit or loss    
Net Interest Income at Risk [Line Items]    
Derivative financial liabilities held for hedging € 74,000,000 € 117,000,000
Discontinued hedges | – Cross currency swaps | - Derivatives    
Net Interest Income at Risk [Line Items]    
Reclassification adjustments on cash flow hedges for which hedged future cash flows are no longer expected to occur, net of tax (1,000,000) 0
Financial assets at fair value through profit or loss | -  fair value hedges    
Net Interest Income at Risk [Line Items]    
Derivative financial assets held for hedging 578,000,000 617,000,000
Financial assets at fair value through profit or loss | Cash flow hedges    
Net Interest Income at Risk [Line Items]    
Derivative financial assets held for hedging 459,000,000 158,000,000
Financial assets at fair value through profit or loss | -  hedges of net investments in foreign operations    
Net Interest Income at Risk [Line Items]    
Derivative financial assets held for hedging € 68,000,000 € 82,000,000