v3.25.4
Fair value of assets and liabilities - Additional information (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of fair value measurement of assets and liabilities [Line Items]      
Financial assets classified as Level 3 based on quoted price € 10,100 € 9,600  
Percentage on financial asset based on unadjusted quoted price 86.20% 87.20%  
Amount of risk neutral designed financial assets € 100 € 100  
Remaining financial assets classified as level 3 using valuation techniques 1,500 1,300  
Financial liabilities measured at fair value 80,532 86,900  
Financial Liabilities classified as Level 3 based on unadjusted quoted price 600 600  
Financial Liabilities designed to be fully neutral in terms of market risk 100 100  
–  Trading securities      
Disclosure of fair value measurement of assets and liabilities [Line Items]      
Transfers from Level 2 into Level 1 , liabilities 200 0  
- Debt securities      
Disclosure of fair value measurement of assets and liabilities [Line Items]      
Transfers from Level 1 into Level 2 300 0  
Transfer from Level 2 to Level 1 400 800  
Level 3      
Disclosure of fair value measurement of assets and liabilities [Line Items]      
Fair value of swap € 11,742 € 11,005 € 9,118
Percentage on financial asset based on unadjusted quoted price 72.70% 75.70%  
Financial liabilities measured at fair value € 802 € 770  
Remaining financial liabilities classified as level 3 using valuation techniques € 100 € 100