v3.25.4
Derivatives and hedge accounting - Cash flow hedging - impact of hedging instruments on the statement of profit or loss and other comprehensive income (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
– Discontinued hedges    
Disclosure of detailed information about hedged items [line items]    
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-)
– Discontinued hedges | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Carrying amount cash flow hedge reserve at the end of the reporting period   89
Amount reclassified from CFH reserve to profit or loss   (51)
– Discontinued hedges | – Cross currency interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Carrying amount cash flow hedge reserve at the end of the reporting period  
Amount reclassified from CFH reserve to profit or loss  
- Derivatives | Cash flow hedges    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period (920) (550)
Carrying amount cash flow hedge reserve at the end of the reporting period (1,635) (2,614)
Amount reclassified from CFH reserve to profit or loss 149 (209)
Change in value of hedging instrument recognised in OCI for the period 799 743
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-) 10 35
- Derivatives | Cash flow hedges | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period (977) (553)
Carrying amount cash flow hedge reserve at the end of the reporting period (1,619) (2,635)
Amount reclassified from CFH reserve to profit or loss 397 20
Change in value of hedging instrument recognised in OCI for the period 602 526
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-) 7 39
- Derivatives | Cash flow hedges | – Cross currency swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period 20 (67)
Carrying amount cash flow hedge reserve at the end of the reporting period (62) (51)
Amount reclassified from CFH reserve to profit or loss (209) (162)
Change in value of hedging instrument recognised in OCI for the period 195 220
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-) 3 (3)
- Derivatives | Cash flow hedges | – Cross currency interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period 37 70
Carrying amount cash flow hedge reserve at the end of the reporting period 47 72
Amount reclassified from CFH reserve to profit or loss (39) (68)
Change in value of hedging instrument recognised in OCI for the period 2 (3)
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-) 1 (2)
- Derivatives | – Discontinued hedges | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Carrying amount cash flow hedge reserve at the end of the reporting period (323)  
Amount reclassified from CFH reserve to profit or loss 7  
- Derivatives | – Discontinued hedges | – Cross currency swaps    
Disclosure of detailed information about hedged items [line items]    
Carrying amount cash flow hedge reserve at the end of the reporting period
Amount reclassified from CFH reserve to profit or loss (1) (4)
- Derivatives | – Discontinued hedges | – Cross currency interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Carrying amount cash flow hedge reserve at the end of the reporting period  
Amount reclassified from CFH reserve to profit or loss  
Lending | Floating rate | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period (1,265) (668)
Carrying amount cash flow hedge reserve at the end of the reporting period (1,157) (2,850)
Amount reclassified from CFH reserve to profit or loss 536 496
Lending | Floating rate | – Cross currency swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period (15) (79)
Carrying amount cash flow hedge reserve at the end of the reporting period (58) (55)
Amount reclassified from CFH reserve to profit or loss (171) (121)
Lending | Floating rate | – Cross currency interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period 37 70
Carrying amount cash flow hedge reserve at the end of the reporting period 47 72
Amount reclassified from CFH reserve to profit or loss (39) (68)
Borrowings | Floating rate | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period 289 114
Carrying amount cash flow hedge reserve at the end of the reporting period (141) 125
Amount reclassified from CFH reserve to profit or loss (146) (425)
Borrowings | Floating rate | – Cross currency swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period 34 12
Carrying amount cash flow hedge reserve at the end of the reporting period (4) 5
Amount reclassified from CFH reserve to profit or loss (38) (37)
Borrowings | Floating rate | – Cross currency interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period
Carrying amount cash flow hedge reserve at the end of the reporting period
Amount reclassified from CFH reserve to profit or loss
Other | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period   1
Carrying amount cash flow hedge reserve at the end of the reporting period   1
Other | – Cross currency swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period
Carrying amount cash flow hedge reserve at the end of the reporting period
Amount reclassified from CFH reserve to profit or loss
Other | – Cross currency interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period
Carrying amount cash flow hedge reserve at the end of the reporting period
Amount reclassified from CFH reserve to profit or loss
Other | Cash flow hedges | – Interest rate swaps    
Disclosure of detailed information about hedged items [line items]    
Change in value of hedged item used for calculating hedge ineffectiveness for the period  
Carrying amount cash flow hedge reserve at the end of the reporting period  
Amount reclassified from CFH reserve to profit or loss