Cover - shares	9 Months Ended
	Sep. 30, 2021	Nov. 03, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-39253
Entity Registrant Name	Opendoor Technologies Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-1515020
Entity Address, Address Line One	410 N. Scottsdale Road,
Entity Address, Address Line Two	Suite 1600
Entity Address, City or Town	Tempe,
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85281
City Area Code	415
Local Phone Number	896-6737
Title of 12(b) Security	Common stock, $0.0001 par value per share
Trading Symbol	OPEN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		612,612,711
Entity Central Index Key	0001801169
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31