| Document | Nov. 29, 2021 |
| Cover Document [Abstract] | |
| Amendment Flag | false |
| Document Type | 8-K |
| Document Period End Date | Nov. 29, 2021 |
| Entity Registrant Name | FEDERAL HOME LOAN BANK OF BOSTON |
| Entity Central Index Key | 0001331463 |
| Entity File Number | 000-51402 |
| Entity Tax Identification Number | 04-6002575 |
| Entity Address, Address Line One | 800 Boylston Street |
| Entity Address, City or Town | Boston, |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02199 |
| City Area Code | (617) |
| Local Phone Number | 292-9600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Incorporation, State or Country Code | X1 |
