v3.26.1
Note 21 Deposits from credit institutions (Details) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks € 44,263 € 36,771
SPAIN    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 7,796 4,676
MEXICO    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 1,848 2,789
TURKEY    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 1,129 1,204
South America [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 3,526 3,363
Europe [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 20,583 17,110
Rest of the world [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 9,380 7,630
Demand deposits at amortized cost [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 6,587 6,764
Demand deposits at amortized cost [Member] | SPAIN    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 1,244 1,039
Demand deposits at amortized cost [Member] | MEXICO    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 1,047 1,825
Demand deposits at amortized cost [Member] | TURKEY    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 57 60
Demand deposits at amortized cost [Member] | South America [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 474 636
Demand deposits at amortized cost [Member] | Europe [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 1,941 1,890
Demand deposits at amortized cost [Member] | Rest of the world [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 1,823 1,315
Time deposits and other [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 19,668 16,700
Time deposits and other [Member] | SPAIN    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 4,276 3,439
Time deposits and other [Member] | MEXICO    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 263 964
Time deposits and other [Member] | TURKEY    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 1,070 873
Time deposits and other [Member] | South America [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 3,052 2,468
Time deposits and other [Member] | Europe [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 4,382 3,513
Time deposits and other [Member] | Rest of the world [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks [1] 6,625 5,442
Repurchase agreements of deposits from credit institutions    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 18,008 13,307
Repurchase agreements of deposits from credit institutions | SPAIN    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 2,276 197
Repurchase agreements of deposits from credit institutions | MEXICO    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 538 0
Repurchase agreements of deposits from credit institutions | TURKEY    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 2 271
Repurchase agreements of deposits from credit institutions | South America [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 0 259
Repurchase agreements of deposits from credit institutions | Europe [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks 14,260 11,707
Repurchase agreements of deposits from credit institutions | Rest of the world [Member]    
Deposits From Banks Breakdown By Geography [Line Items]    
Deposits from banks € 931 € 874
[1]
(1) Subordinated deposits are included amounting to €14 million and €104 million as of June 30, 2026 and December 31, 2025, respectively.