Document and Entity Information - USD ($)	3 Months Ended
	Mar. 31, 2018	Apr. 27, 2018	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	Mar. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
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		371,981,518