v3.25.4
Cover Page - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2025
Jan. 31, 2026
Jun. 30, 2025
Entity Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Current Fiscal Year End Date --12-31    
Document Period End Date Dec. 31, 2025    
Document Transition Report false    
Entity File Number 1-9924    
Entity Registrant Name Citigroup Inc    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 52-1568099    
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    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction false    
Entity Shell Company false    
Entity Public Float     $ 156.2
Entity Common Stock, Shares Outstanding   1,749,319,009  
Documents Incorporated by Reference Portions of the registrant’s proxy statement for the annual meeting of stockholders scheduled to be held on May 20, 2026 are incorporated by reference in this Form 10-K in response to Items 10, 11, 12, 13 and 14 of Part III.    
Entity Central Index Key 0000831001    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Amendment Flag false    
Common Stock, par value $.01 per share      
Entity Information [Line Items]      
Title of 12(b) Security Common Stock, par value $.01 per share    
Trading Symbol C    
Security Exchange Name NYSE    
Depositary Shares, each representing a 1/1,000th interest in a share of 6.250% Noncumulative Preferred Stock, Series II      
Entity Information [Line Items]      
Title of 12(b) Security Dep Shs, represent 1/1,000th interest in a share of 6.250% Noncum Pref Stk, Ser II    
Trading Symbol C PR R    
Security Exchange Name NYSE    
7.625% Trust Preferred Securities of Citigroup Capital III (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
Title of 12(b) Security 7.625% TRUPs of Cap III (and registrant’s guaranty)    
Trading Symbol C/36Y    
Security Exchange Name NYSE    
7.875% Fixed Rate / Floating Rate Trust Preferred Securities (TruPS®) of Citigroup Capital XIII (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
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    
Medium-Term Senior Notes, Series N, Callable Fixed Rate Notes Due April 26, 2028 of CGMHI (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
Title of 12(b) Security MTN, Series N, Callable Fixed Rate Notes Due Apr 2028 of CGMHI (and registrant’s guaranty)    
Trading Symbol C/28    
Security Exchange Name NYSE    
Medium-Term Senior Notes, Series N, Floating Rate Notes Due September 17, 2026 of CGMHI (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
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    
Medium-Term Senior Notes, Series N, Floating Rate Notes Due September 15, 2028 of CGMHI (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
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    
Medium-Term Senior Notes, Series N, Floating Rate Notes Due October 6, 2028 of CGMHI (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
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    
Medium-Term Senior Notes, Series N, Floating Rate Notes Due March 21, 2029 of CGMHI (and registrant’s guaranty with respect thereto)      
Entity Information [Line Items]      
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