v3.25.4
Commission and Fee Income - Disaggregation of revenues by product type and business segment - based on IFRS 15 (Detail: Text Values) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Commissions and Fee Income [Abstract]    
Performance fee revenue recognized prior to receipt of actual distribution € 165 € 0
Disclosure of performance obligations [line items]    
Balance of receivables from commission and fee income 1,100 831
Balance of contract liabilities associated to commission and fee income 73 84
Not later than one year and later than four years    
Disclosure of performance obligations [line items]    
Unsatisfied performance obligations € 173 € 250