| Cover | Dec. 15, 2020 |
| Entity Listings [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 15, 2020 |
| Entity File Number | 001-38661 |
| Entity Registrant Name | Elanco Animal Health Incorporated |
| Entity Central Index Key | 0001739104 |
| Entity Tax Identification Number | 82-5497352 |
| Entity Incorporation, State or Country Code | IN |
| Entity Address, Address Line One | 2500 Innovation Way |
| Entity Address, City or Town | Greenfield |
| Entity Address, State or Province | IN |
| Entity Address, Postal Zip Code | 46140 |
| City Area Code | 877 |
| Local Phone Number | 352-6261 |
| 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] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Common stock, no par value |
| Trading Symbol | ELAN |
| Security Exchange Name | NYSE |
| 5.00 Percent Tangible Equity Units [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | 5.00% Tangible Equity Units |
| Trading Symbol | ELAT |
| Security Exchange Name | NYSE |
