| Cover | Dec. 18, 2023 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 18, 2023 |
| Entity File Number | 1-9924 |
| Entity Registrant Name | Citigroup Inc. |
| Entity Central Index Key | 0000831001 |
| Entity Tax Identification Number | 52-1568099 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 388 Greenwich Street |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| 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 |
| Common Stock [Member] | |
| Title of 12(b) Security | Common Stock, par value $.01 per share |
| Trading Symbol | C |
| Security Exchange Name | NYSE |
| Sec Dep Shsrepresent 11000thinterestinashareof 7125 Percent Fix Float Rate Noncum Pref Stk Ser J [Member] | |
| Title of 12(b) Security | Dep Shs, represent 1/1,000th interest in a share of 7.125% Fix/Float Rate Noncum Pref Stk, Ser J |
| Trading Symbol | C Pr J |
| Security Exchange Name | NYSE |
| Sec 7625 Percent T R U Psof Cap I I Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | 7.625% TRUPs of Cap III (and registrant’s guaranty) |
| Trading Symbol | C/36Y |
| Security Exchange Name | NYSE |
| Sec 7875 Percent F X D F R N Tru P Sof Cap X I I Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | 7.875% FXD / FRN TruPS of Cap XIII (and registrant’s guaranty) |
| Trading Symbol | C N |
| Security Exchange Name | NYSE |
| Sec M T N Series N Callable Step Up Coupon Notes Due Mar 2036of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Callable Step-Up Coupon Notes Due Mar 2036 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/36A |
| Security Exchange Name | NYSE |
| Sec M T N Series N Callable Step Up Coupon Notes Due Feb 2036of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Callable Step-Up Coupon Notes Due Feb 2036 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/36 |
| Security Exchange Name | NYSE |
| Sec M T N Series N Callable Fixed Rate Notes Due Dec 2035of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Callable Fixed Rate Notes Due Dec 2035 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/35 |
| Security Exchange Name | NYSE |
| Sec M T N Series N Floating Rate Notes Due Sec April 262028of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Floating Rate Notes Due April 26, 2028 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/28 |
| Security Exchange Name | NYSE |
| Sec M T N Series N Floating Rate Notes Due Sept 2026of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Floating Rate Notes Due Sept 2026 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/26 |
| Security Exchange Name | NYSE |
| Sec M T N Series N Floating Rate Notes Due Sept 2028of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Floating Rate Notes Due Sept 2028 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/28A |
| Security Exchange Name | NYSE |
| Sec M T N Series N Floating Rate Notes Due Oct 2028of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Floating Rate Notes Due Oct 2028 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/28B |
| Security Exchange Name | NYSE |
| Sec M T N Series N Floating Rate Notes Due Mar 2029of C G M H Iandregistrantsguaranty [Member] | |
| Title of 12(b) Security | MTN, Series N, Floating Rate Notes Due Mar 2029 of CGMHI (and registrant’s guaranty) |
| Trading Symbol | C/29A |
| Security Exchange Name | NYSE |
