v3.25.4
Condensed financial information of the parent company - Five-year schedule of maturities of debt (Details) - Parent company - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
Subordinated Loans    
Condensed Financial Statements, Captions [Line Items]    
Borrowings € 18,429 € 18,522
Subordinated Loans | Within 1 year    
Condensed Financial Statements, Captions [Line Items]    
Borrowings
Subordinated Loans | More than 1 year but less than 2 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings
Subordinated Loans | More than 2 years but less than 3 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings
Subordinated Loans | More than 3 years but less than 4 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings
Subordinated Loans | More than 4 years but less than 5 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings
Subordinated Loans | More than 5 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 10,735 10,035
Subordinated Loans | Maturity not applicable    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 7,695 8,487
Debenture loans    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 49,562 49,751
Debenture loans | Within 1 year    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 3,284 1,010
Debenture loans | More than 1 year but less than 2 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 6,859 8,053
Debenture loans | More than 2 years but less than 3 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 7,180 7,401
Debenture loans | More than 3 years but less than 4 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 7,326 7,523
Debenture loans | More than 4 years but less than 5 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 7,747 6,220
Debenture loans | More than 5 years    
Condensed Financial Statements, Captions [Line Items]    
Borrowings 17,167 19,544
Debenture loans | Maturity not applicable    
Condensed Financial Statements, Captions [Line Items]    
Borrowings