Document and Entity Information - USD ($)	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	WELLTOWER INC. /DE/
Entity Central Index Key	0000766704
Document Type	10-Q
Document Period End date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 27,562,002,967
Entity Common Stock Shares Outstanding		370,356,835