v3.26.1
Cover Page
12 Months Ended
Dec. 31, 2025
Cover [Abstract]  
Document Type 6-K
Entity File Number 001-12518
Entity Registrant Name Banco Santander, S.A.
Entity Address, Address Line One 28660 Boadilla del Monte (Madrid)
Entity Address, Country ES
Entity Central Index Key 0000891478
Amendment Flag false
Current Fiscal Year End Date --12-31
Document Period End Date Dec. 31, 2025
Document Fiscal Year Focus 2025
Document Fiscal Period Focus FY