v3.26.1
Risk management - Schedule of exposure to risk, forborne loans (Details)
€ in Millions
 12 Months Ended
Dec. 31, 2025
EUR (€)
transactions
Dec. 31, 2024
EUR (€)
Dec. 31, 2023
EUR (€)
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € 300,026 € 283,497 € 243,203
Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (520) € (349) € (286)
Forborne loan portfolio | Credit risk | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 3,490,210    
Forborne loan portfolio | Credit risk | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 558,424    
Forborne loan portfolio | Credit risk | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 7,145    
Forborne loan portfolio | Credit risk | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 4,715    
Forborne loan portfolio | Credit risk | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 1,916,935    
Forborne loan portfolio | Credit risk | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 323,505    
Forborne loan portfolio | Credit risk | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 2,923    
Forborne loan portfolio | Credit risk | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 2,663    
Forborne loan portfolio | Credit risk | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 9,751    
Forborne loan portfolio | Credit risk | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 15,484    
Forborne loan portfolio | Credit risk | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 5,354    
Forborne loan portfolio | Credit risk | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 7,980    
Forborne loan portfolio | Credit risk | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (6,480)    
Forborne loan portfolio | Credit risk | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (5,508)    
Forborne loan portfolio | Credit risk | Credit entities | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 0    
Forborne loan portfolio | Credit risk | Credit entities | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 0    
Forborne loan portfolio | Credit risk | Credit entities | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 0    
Forborne loan portfolio | Credit risk | Credit entities | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 0    
Forborne loan portfolio | Credit risk | Credit entities | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 0    
Forborne loan portfolio | Credit risk | Credit entities | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 0    
Forborne loan portfolio | Credit risk | Credit entities | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 0    
Forborne loan portfolio | Credit risk | Credit entities | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 0    
Forborne loan portfolio | Credit risk | Credit entities | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 0    
Forborne loan portfolio | Credit risk | Credit entities | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 0    
Forborne loan portfolio | Credit risk | Credit entities | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 0    
Forborne loan portfolio | Credit risk | Credit entities | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 0    
Forborne loan portfolio | Credit risk | Credit entities | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 0    
Forborne loan portfolio | Credit risk | Credit entities | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € 0    
Forborne loan portfolio | Credit risk | Public sector | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 14    
Forborne loan portfolio | Credit risk | Public sector | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 9    
Forborne loan portfolio | Credit risk | Public sector | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 5    
Forborne loan portfolio | Credit risk | Public sector | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 0    
Forborne loan portfolio | Credit risk | Public sector | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 5    
Forborne loan portfolio | Credit risk | Public sector | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 9    
Forborne loan portfolio | Credit risk | Public sector | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 5    
Forborne loan portfolio | Credit risk | Public sector | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 0    
Forborne loan portfolio | Credit risk | Public sector | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 6    
Forborne loan portfolio | Credit risk | Public sector | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 7    
Forborne loan portfolio | Credit risk | Public sector | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2    
Forborne loan portfolio | Credit risk | Public sector | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 7    
Forborne loan portfolio | Credit risk | Public sector | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (8)    
Forborne loan portfolio | Credit risk | Public sector | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (8)    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 933    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 462    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 117    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 15    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 579    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 259    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 22    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 11    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 94    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 182    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 50    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 75    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (94)    
Forborne loan portfolio | Credit risk | Other financial institutions and: individual shareholder | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (89)    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 489,192    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 42,700    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 3,271    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 923    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 296,008    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 26,767    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 1,166    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 420    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 5,095    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 5,596    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,901    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,585    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (2,713)    
Forborne loan portfolio | Credit risk | Non-financial institutions and individual shareholder | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (2,420)    
Forborne loan portfolio | Credit risk | Construction and property development | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 249    
Forborne loan portfolio | Credit risk | Construction and property development | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 523    
Forborne loan portfolio | Credit risk | Construction and property development | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 695    
Forborne loan portfolio | Credit risk | Construction and property development | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 4    
Forborne loan portfolio | Credit risk | Construction and property development | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 167    
Forborne loan portfolio | Credit risk | Construction and property development | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 264    
Forborne loan portfolio | Credit risk | Construction and property development | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 115    
Forborne loan portfolio | Credit risk | Construction and property development | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 4    
Forborne loan portfolio | Credit risk | Construction and property development | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 21    
Forborne loan portfolio | Credit risk | Construction and property development | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 739    
Forborne loan portfolio | Credit risk | Construction and property development | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 3    
Forborne loan portfolio | Credit risk | Construction and property development | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 156    
Forborne loan portfolio | Credit risk | Construction and property development | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (75)    
Forborne loan portfolio | Credit risk | Construction and property development | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (50)    
Forborne loan portfolio | Credit risk | Other warehouses | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 3,000,071    
Forborne loan portfolio | Credit risk | Other warehouses | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 515,253    
Forborne loan portfolio | Credit risk | Other warehouses | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 3,752    
Forborne loan portfolio | Credit risk | Other warehouses | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 3,777    
Forborne loan portfolio | Credit risk | Other warehouses | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 1,620,343    
Forborne loan portfolio | Credit risk | Other warehouses | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 296,470    
Forborne loan portfolio | Credit risk | Other warehouses | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 1,730    
Forborne loan portfolio | Credit risk | Other warehouses | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 2,232    
Forborne loan portfolio | Credit risk | Other warehouses | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 4,556    
Forborne loan portfolio | Credit risk | Other warehouses | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 9,699    
Forborne loan portfolio | Credit risk | Other warehouses | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,401    
Forborne loan portfolio | Credit risk | Other warehouses | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 5,313    
Forborne loan portfolio | Credit risk | Other warehouses | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (3,665)    
Forborne loan portfolio | Credit risk | Other warehouses | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (2,991)    
Non-current assets or disposal groups classified as held for sale | Credit risk | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 13,499    
Non-current assets or disposal groups classified as held for sale | Credit risk | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 4,630    
Non-current assets or disposal groups classified as held for sale | Credit risk | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 406    
Non-current assets or disposal groups classified as held for sale | Credit risk | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 14    
Non-current assets or disposal groups classified as held for sale | Credit risk | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 6,901    
Non-current assets or disposal groups classified as held for sale | Credit risk | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of transactions (in loans) | transactions 1,720    
Non-current assets or disposal groups classified as held for sale | Credit risk | Credit impaired | Real estate guarantee      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered € 110    
Non-current assets or disposal groups classified as held for sale | Credit risk | Credit impaired | Rest of real guarantees      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Maximum amount of the actual collateral that can be considered 5    
Non-current assets or disposal groups classified as held for sale | Credit risk | Gross carrying amount | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 261    
Non-current assets or disposal groups classified as held for sale | Credit risk | Gross carrying amount | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 566    
Non-current assets or disposal groups classified as held for sale | Credit risk | Gross carrying amount | Credit impaired | Without collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 120    
Non-current assets or disposal groups classified as held for sale | Credit risk | Gross carrying amount | Credit impaired | Of which property collateral      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 235    
Non-current assets or disposal groups classified as held for sale | Credit risk | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (171)    
Non-current assets or disposal groups classified as held for sale | Credit risk | Accumulated impairment | Credit impaired      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets € (145)