| Document and Entity Information | Dec. 02, 2024 |
| Cover [Abstract] | |
| Entity Registrant Name | CITIGROUP INC |
| Entity Address, State or Province | NY |
| Amendment Flag | false |
| Entity Central Index Key | 0000831001 |
| Current Fiscal Year End Date | --12-31 |
| Document Type | 8-K |
| Document Period End Date | Dec. 02, 2024 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-9924 |
| Entity Tax Identification Number | 52-1568099 |
| Entity Address, Address Line One | 388 Greenwich |
| Entity Address, City or Town | New York |
| Entity Address, Postal Zip Code | 10013 |
| City Area Code | (212) |
| Local Phone Number | 559-1000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
