| Document and Entity Information | Apr. 17, 2020 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0000766704 |
| Document Type | 8-K |
| Document Period End Date | Apr. 17, 2020 |
| Entity Registrant Name | Welltower Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-8923 |
| Entity Tax Identification Number | 34-1096634 |
| Entity Address, Address Line One | 4500 Dorr Street |
| Entity Address, City or Town | Toledo |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 43615 |
| City Area Code | (419) |
| Local Phone Number | 247-2800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common stock, $1.00 par value per share |
| Trading Symbol | WELL |
| Security Exchange Name | NYSE |
| M 4.800 Notes Due 20282 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 4.800% Notes due 2028 |
| Trading Symbol | WELL28 |
| Security Exchange Name | NYSE |
| M 4.500 Notes Due 20341 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 4.500% Notes due 2034 |
| Trading Symbol | WELL34 |
| Security Exchange Name | NYSE |
