v3.26.3
Document and Entity Information
Nov. 06, 2026
Document And Entity Information [Line Items]  
Amendment Flag false
Entity Central Index Key 0000811830
Document Type 8-K
Document Period End Date Nov. 06, 2026
Entity Registrant Name Santander Holdings USA, Inc.
Entity File Number 1-16581
Entity Tax Identification Number 23-2453088
Entity Address, Address Line One 75 State Street
Entity Address, City or Town Boston
Entity Address, State or Province MA
Entity Address, Postal Zip Code 02109
City Area Code (800)
Local Phone Number 493-8219
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Security 12b Title Depositary Shares, Each Representing a 1/1,000th Interest in a Share of Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series H
Trading Symbol SNUS PF H
Security Exchange Name NYSE
Entity Emerging Growth Company false
VA  
Document And Entity Information [Line Items]  
Entity Incorporation State Country Code VA