v3.26.1
Loans and advances to customers - Narrative (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Loans And Advances To Customers Table [Line Items]      
Maximum exposure to credit risk € 888,496 € 908,963 € 914,491
Loans and receivables      
Loans And Advances To Customers Table [Line Items]      
Impairment losses charged to income for the year 12,535 12,136 12,298
Reversal of impairment loss recognised in profit or loss 1,791 1,600 1,587
Securitized loans and loans and advances to customers      
Loans And Advances To Customers Table [Line Items]      
Recognised assets representing continuing involvement in fully derecognised loans 12,174 14,919 13,923
Financial instruments credit-impaired | Loans and receivables      
Loans And Advances To Customers Table [Line Items]      
Written-off assets 51,435 49,939 48,138
Financial instruments purchased credit impaired      
Loans And Advances To Customers Table [Line Items]      
Maximum exposure to credit risk 334 559 743
Financial instruments purchased credit impaired | Customers      
Loans And Advances To Customers Table [Line Items]      
Maximum exposure to credit risk 307 515 694
Financial instruments purchased credit impaired | Customers | Business combinations carried out      
Loans And Advances To Customers Table [Line Items]      
Maximum exposure to credit risk 46    
Without considering the Public Administration      
Loans And Advances To Customers Table [Line Items]      
Loans and advances to customers 1,024,071 1,046,039 1,032,063
Without considering the Public Administration | Financial instruments not credit-impaired      
Loans And Advances To Customers Table [Line Items]      
Loans and advances to customers 954,533 1,012,389 998,010
Spain      
Loans And Advances To Customers Table [Line Items]      
Maximum exposure to credit risk € 201,013 198,936 205,994
A | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Credit exposure percentage 25.60%    
AAA | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Credit exposure percentage 3.60%    
AA | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Credit exposure percentage 26.40%    
BBB | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Credit exposure percentage 27.50%    
Below BBB | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Credit exposure percentage 16.40%    
No Rating | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Credit exposure percentage 0.50%    
Gross carrying amount | Financial instruments credit-impaired      
Loans And Advances To Customers Table [Line Items]      
Loans and advances to customers € 31,577    
Gross carrying amount | Rest of the world | Public sector      
Loans And Advances To Customers Table [Line Items]      
Loans and advances to customers 16,248 13,593 11,530
Gross carrying amount | A | Spain | Public sector      
Loans And Advances To Customers Table [Line Items]      
Loans and advances to customers 18,127 16,562 15,544
Accumulated impairment | Debt securities      
Loans And Advances To Customers Table [Line Items]      
Impairment losses charged to income for the year 182 226 24
Reversal of impairment loss recognised in profit or loss 56 € 8 € 12
Accumulated impairment | Financial instruments credit-impaired      
Loans And Advances To Customers Table [Line Items]      
Loans and advances to customers € (13,527)