v3.25.2
DEBT - Long-Term Debt (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Debt Instrument    
Long-term debt, at fair value $ 317,761 $ 287,300
Trust preferred securities 1,600 1,600
Citigroup Inc.    
Debt Instrument    
Long-term debt, at fair value 173,516 164,024
Bank    
Debt Instrument    
Long-term debt, at fair value 43,513 35,470
Bank | Senior notes    
Debt Instrument    
Collateralized long-term advances from Federal Home Loan Bank 6,500 8,500
Broker-dealer and other    
Debt Instrument    
Long-term debt, at fair value $ 100,732 $ 87,806