| Document and Entity Information | Jan. 03, 2024 |
| Cover [Abstract] | |
| Security Exchange Name | NASDAQ |
| Amendment Flag | false |
| Entity Central Index Key | 0001832415 |
| Document Type | 8-K |
| Document Period End Date | Jan. 03, 2024 |
| Entity Registrant Name | Better Therapeutics, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39864 |
| Entity Tax Identification Number | 85-3472546 |
| Entity Address, Address Line One | 548 Market Street |
| Entity Address, Address Line Two | #49404 |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94104 |
| City Area Code | 415 |
| Local Phone Number | 887-2311 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock |
| Trading Symbol | BTTX |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
