| Cover | Nov. 12, 2024 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 12, 2024 |
| Entity File Number | 001-41047 |
| Entity Registrant Name | Chain Bridge I |
| Entity Central Index Key | 0001845149 |
| Entity Tax Identification Number | 98-1578955 |
| Entity Incorporation, State or Country Code | E9 |
| Entity Address, Address Line One | 8 The Green |
| Entity Address, Address Line Two | #17538 |
| Entity Address, City or Town | Dover |
| Entity Address, State or Province | DE |
| Entity Address, Postal Zip Code | 19901 |
| City Area Code | 202 |
| Local Phone Number | 656-4257 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
| Unitseachconsistingofone Class Aordinaryshareandonehalfofoneredeemable Warranttoacquireone Class Aordinaryshare [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Units, each consisting of one Class A ordinary share and one-half of one redeemable Warrant to acquire one Class A ordinary share |
| Trading Symbol | CBRGU |
| Security Exchange Name | NASDAQ |
| Common Class A [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Class A ordinary shares, par value $0.0001 per share |
| Trading Symbol | CBRG |
| Security Exchange Name | NASDAQ |
