v3.26.1
Financial liabilities - Disclosure of composition of debt instruments excluding promissory notes (Details) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Bonds and debentures outstanding        
Disclosure of financial liabilities [line items]        
Financial liabilities € 269,438 € 253,893 € 244,891 € 252,765
Subordinated        
Disclosure of financial liabilities [line items]        
Financial liabilities 30,911 28,859 € 30,951 € 35,461
Debt instruments        
Disclosure of financial liabilities [line items]        
Financial liabilities 348,067 324,390    
Debt instruments | Bonds and debentures outstanding        
Disclosure of financial liabilities [line items]        
Financial liabilities 269,438 253,893    
Debt instruments | Subordinated        
Disclosure of financial liabilities [line items]        
Financial liabilities 30,911 28,859    
Debt instruments | Promissory notes and other securities        
Disclosure of financial liabilities [line items]        
Financial liabilities € 47,718 € 41,638