| Document and Entity Information | Dec. 14, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 14, 2023 |
| Entity File Number | 001-11460 |
| Entity Registrant Name | Eterna Therapeutics Inc. |
| Entity Central Index Key | 0000748592 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 31-1103425 |
| Entity Address, Address Line One | 1035 Cambridge Street |
| Entity Address, Address Line Two | Suite 18A |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02141 |
| City Area Code | 212 |
| Local Phone Number | 582-1199 |
| Title of 12(b) Security | Common Stock, par value $0.005 per share |
| Trading Symbol | ERNA |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
