v3.25.4
Fair value of assets and liabilities - Methods applied in determining fair values of financial assets and liabilities (carried at fair value) (Detail) - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss € 133,157 € 137,580
Financial assets at fair value through other comprehensive income 56,662 46,389
Financial liabilities at fair value through profit or loss 80,532 86,900
–  Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 8,839 9,966
–  Deposits    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 47,120 45,014
–  Trading securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 2,554 3,653
- Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 22,019 28,267
Loans and receivables    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 74,352 68,782
Financial assets at fair value through other comprehensive income 3,238 1,608
- Equity securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 21,583 20,945
Financial assets at fair value through other comprehensive income 2,607 2,562
- Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 11,219 15,586
- Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through other comprehensive income 50,817 42,219
- Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 26,003 32,268
Level 1    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 27,937 28,275
Financial assets at fair value through other comprehensive income 51,829 42,151
Financial liabilities at fair value through profit or loss 4,226 5,131
Level 1 | –  Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 1,540 1,455
Level 1 | –  Deposits    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 0 0
Level 1 | –  Trading securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 2,534 3,631
Level 1 | - Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 152 45
Level 1 | Loans and receivables    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 0 0
Financial assets at fair value through other comprehensive income 0 0
Level 1 | - Equity securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 21,392 20,789
Financial assets at fair value through other comprehensive income 2,301 2,292
Level 1 | - Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 6,492 7,485
Level 1 | - Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through other comprehensive income 49,529 39,859
Level 1 | - Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 52 1
Level 2    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 93,785 98,571
Financial assets at fair value through other comprehensive income 4,526 3,967
Financial liabilities at fair value through profit or loss 75,505 80,998
Level 2 | –  Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 7,284 8,445
Level 2 | –  Deposits    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 47,120 45,014
Level 2 | –  Trading securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 11 12
Level 2 | - Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 21,090 27,528
Level 2 | Loans and receivables    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 65,811 62,168
Financial assets at fair value through other comprehensive income 3,238 1,608
Level 2 | - Equity securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 4 15
Financial assets at fair value through other comprehensive income 0 0
Level 2 | - Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 2,793 4,596
Level 2 | - Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through other comprehensive income 1,288 2,360
Level 2 | - Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 25,178 31,792
Level 3    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 11,435 10,734
Financial assets at fair value through other comprehensive income 307 270
Financial liabilities at fair value through profit or loss 802 770
Level 3 | –  Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 15 67
Level 3 | –  Deposits    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 0 0
Level 3 | –  Trading securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 9 10
Level 3 | - Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial liabilities at fair value through profit or loss 777 694
Level 3 | Loans and receivables    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 8,542 6,614
Financial assets at fair value through other comprehensive income 0 0
Level 3 | - Equity securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 187 141
Financial assets at fair value through other comprehensive income 307 270
Level 3 | - Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 1,934 3,505
Level 3 | - Debt securities    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss 1,934 3,504
Financial assets at fair value through other comprehensive income 0 0
Financial liabilities at fair value through profit or loss 9 10
Level 3 | - Derivatives    
Disclosure of fair value measurement of assets and liabilities [Line Items]    
Financial assets at fair value through profit or loss € 773 € 475