Cover Page - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	001-16581
Entity Registrant Name	SANTANDER HOLDINGS USA, INC.
Entity Incorporation, State or Country Code	VA
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	617
Local Phone Number	346-7200
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		530,391,043
Entity Central Index Key	0000811830
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31