v3.26.1
Cover
Aug. 04, 2026
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Aug. 04, 2026
Entity File Number 1-16581
Entity Registrant Name Santander Holdings USA, Inc.
Entity Central Index Key 0000811830
Entity Tax Identification Number 23-2453088
Entity Incorporation, State or Country Code VA
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
Entity Emerging Growth Company false