v3.26.1
Financial instruments carried at fair value - Sensitivity analysis by type of instrument (Detail) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Positive fair value
movement from
using reasonable
possible
alternatives | Valuation
technique
unobservable
parameters
(Level 3)    
Securities:    
Debt securities [1] € 167 € 237
Commercial mortgage-backed securities [1] 15 13
Mortgage and other asset-backed securities [1] 14 10
Corporate, sovereign and other debt securities [1] 138 214
Equity securities [1] 109 102
Derivatives:    
Credit derivatives [1] 275 261
Equity [1] 116 74
Interest related [1] 763 660
Foreign Exchange [1] 76 64
Other [1] 239 222
Loans [1] 426 475
Other [1] 0 0
Total [1] 2,171 2,094
Positive fair value
movement from
using reasonable
possible
alternatives | Valuation technique unobservable parameters (Level 3)    
Derivatives:    
Total 2,200 2,100
Negative fair value
movement from
using reasonable
possible
alternatives | Valuation
technique
unobservable
parameters
(Level 3)    
Securities:    
Debt securities [1] 144 219
Commercial mortgage-backed securities [1] 15 13
Mortgage and other asset-backed securities [1] 14 9
Corporate, sovereign and other debt securities [1] 115 197
Equity securities [1] 81 74
Derivatives:    
Credit derivatives [1] 159 127
Equity [1] 56 36
Interest related [1] 416 339
Foreign Exchange [1] 43 46
Other [1] 84 61
Loans [1] 364 394
Other [1] 0 0
Total [1] 1,346 1,294
Negative fair value
movement from
using reasonable
possible
alternatives | Valuation technique unobservable parameters (Level 3)    
Derivatives:    
Total € 1,300 € 1,300
[1] Where the exposure to an unobservable parameter is offset across different instruments then only the net impact is disclosed in the table