v3.25.4
Derivatives and hedge accounting - Maturity derivatives designated in cash flow hedging (Details) - - Derivatives - Cash flow hedges - Net payer and receiver swap - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
– Interest rate swaps    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument € (61,897) € (50,886)
– Interest rate swaps | Less than 1 month    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (2,023) (1,805)
– Interest rate swaps | 1 to 3 months    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (3,542) (768)
– Interest rate swaps | 3 to 12 months    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (6,217) (10,590)
– Interest rate swaps | 1 to 2 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (15,357) (13,389)
– Interest rate swaps | 2 to 3 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (14,152) (10,551)
– Interest rate swaps | 3 to 4 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (4,549) (6,040)
– Interest rate swaps | 4 to 5 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (4,381) (4,522)
– Interest rate swaps | >5 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (11,676) (3,222)
– Cross currency swaps    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (1,210) (3,619)
– Cross currency swaps | Less than 1 month    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument 456
– Cross currency swaps | 1 to 3 months    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument 964 (241)
– Cross currency swaps | 3 to 12 months    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument 654 (972)
– Cross currency swaps | 1 to 2 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (1,271) 122
– Cross currency swaps | 2 to 3 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (446) (1,029)
– Cross currency swaps | 3 to 4 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument 607 (262)
– Cross currency swaps | 4 to 5 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (601) (238)
– Cross currency swaps | >5 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (1,572) (999)
– Cross currency interest rate swaps    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (2,765) (2,887)
– Cross currency interest rate swaps | Less than 1 month    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument
– Cross currency interest rate swaps | 1 to 3 months    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument
– Cross currency interest rate swaps | 3 to 12 months    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (25)
– Cross currency interest rate swaps | 1 to 2 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (1,246)
– Cross currency interest rate swaps | 2 to 3 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (1,518) (1,283)
– Cross currency interest rate swaps | 3 to 4 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument (1,578)
– Cross currency interest rate swaps | 4 to 5 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument
– Cross currency interest rate swaps | >5 years    
Disclosure of detailed information about hedging instruments [line items]    
Nominal amount of hedging instrument