v3.26.1
Other disclosures - Disclosure of financing for construction and real estate business in Spain (Details) - Spain - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Construction and property development loans    
Disclosure of credit risk exposure [line items]    
Financial assets € 3,157 € 2,967
Gross carrying amount | Construction and property development loans    
Disclosure of credit risk exposure [line items]    
Financial assets 3,172 2,984
Written-off assets 232 240
Gross carrying amount | Construction and property development loans | Credit impaired    
Disclosure of credit risk exposure [line items]    
Financial assets 17 31
Excess over collateral value | Construction and property development loans    
Disclosure of credit risk exposure [line items]    
Risk exposure 98 211
Excess over collateral value | Construction and property development loans | Credit impaired    
Disclosure of credit risk exposure [line items]    
Risk exposure 0 0
Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets (1,037) (1,086)
Accumulated impairment | Construction and property development loans    
Disclosure of credit risk exposure [line items]    
Financial assets (15) (17)
Accumulated impairment | Construction and property development loans | Credit impaired    
Disclosure of credit risk exposure [line items]    
Financial assets € (8) € (11)