v3.26.1
Financial Instruments carried at fair value - Sensitivity analysis by type (Detail: Text Values)
€ in Millions
6 Months Ended
Jun. 30, 2026
EUR (€)
Dec. 31, 2025
EUR (€)
Sensitivity Analysis by Type of Instrument [Line Items]    
Changes in positive fair value movement € 77  
Changes in negative fair value movement € 51  
Percentage change in positive fair value movements 0.04  
Percentage change in negative fair value movements 0.04  
Positive fair value
movement from
using reasonable
possible
alternatives | Valuation technique unobservable parameters (Level 3)    
Sensitivity Analysis by Type of Instrument [Line Items]    
Sensitivity analysis by type of instrument € 2,200 € 2,100
Negative fair value
movement from
using reasonable
possible
alternatives | Valuation technique unobservable parameters (Level 3)    
Sensitivity Analysis by Type of Instrument [Line Items]    
Sensitivity analysis by type of instrument € 1,300 € 1,300