| Cover | Jul. 11, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 11, 2023 |
| Entity File Number | 001-40583 |
| Entity Registrant Name | AltC Acquisition Corp. |
| Entity Central Index Key | 0001849056 |
| Entity Tax Identification Number | 85-2292473 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 12 |
| Entity Address, Address Line Two | th |
| Entity Address, Address Line Three | Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10019 |
| City Area Code | (212) |
| Local Phone Number | 380-7500 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Shares of Class A common stock, par value $0.0001 per share |
| Trading Symbol | ALCC |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
