DEBT (Details 2) (USD $)							6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2011 Citigroup Parent Company	Dec. 31, 2010 Citigroup Parent Company	Jun. 30, 2011 Bank	Dec. 31, 2010 Bank	Jun. 30, 2011 Citigroup Global Markets Holdings Inc. (CGMHI) Revolving line of credit facility	Jun. 30, 2011 Non-bank	Dec. 31, 2010 Non-bank	Jun. 30, 2011 Citigroup Funding Inc. (CFI)	Dec. 31, 2010 Citigroup Funding Inc. (CFI)	Jun. 30, 2011 Junior subordinated notes relating to trust preferred securities	Dec. 31, 2010 Junior subordinated notes relating to trust preferred securities	Jun. 30, 2011 Federal Deposit Insurance Corporation (FDIC)
Long-Term Debt:
Total long-term debt	$ 352,458,000,000	$ 381,183,000,000	$ 185,846,000,000	$ 191,944,000,000	$ 95,751,000,000	$ 113,234,000,000		$ 70,861,000,000	$ 76,005,000,000			$ 16,077,000,000	$ 18,131,000,000
Collateralized advances from Federal Home Loan Bank, long-term					16,000,000,000	18,200,000,000
Long-term debt guaranteed by the FDIC	50,500,000,000
Carrying value of Principal-Protected Trust Securities										302,000,000	364,000,000
Amount drawn down on long-term financing facilities with unaffiliated banks							600,000,000
Amount drawn down on long-term financing facilities guaranteed by Citigroup							150,000,000
Notice period banks are required to give CGMHI prior to terminating financing facilities (in years)							1
Aggregate annual maturities of long-term debt obligations
2011														12,500,000,000
2012														$ 38,000,000,000