DEBT (Details 2) (USD $)							9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Citigroup Parent Company	Dec. 31, 2010 Citigroup Parent Company	Sep. 30, 2011 Bank	Dec. 31, 2010 Bank	Sep. 30, 2011 Citigroup Global Markets Holdings Inc. (CGMHI) Revolving line of credit facility Y	Sep. 30, 2011 Non-bank	Dec. 31, 2010 Non-bank	Sep. 30, 2011 Citigroup Funding Inc. (CFI)	Dec. 31, 2010 Citigroup Funding Inc. (CFI)	Sep. 30, 2011 Junior subordinated notes relating to trust preferred securities	Dec. 31, 2010 Junior subordinated notes relating to trust preferred securities	Sep. 30, 2011 Federal Deposit Insurance Corporation (FDIC)
Long-Term Debt:
Total long-term debt	$ 333,824,000,000	$ 381,183,000,000	$ 185,952,000,000	$ 191,944,000,000	$ 80,808,000,000	$ 113,234,000,000		$ 67,064,000,000	$ 76,005,000,000			$ 16,089,000,000	$ 18,131,000,000
Collateralized advances from Federal Home Loan Bank, long-term					11,000,000,000	18,200,000,000
Long-term debt guaranteed by the FDIC	44,000,000,000
Carrying value of senior notes										232,000,000	364,000,000
Amount drawn down on long-term financing facilities with unaffiliated banks							900,000,000
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
Remaining maturity amount of debt														6,000,000,000
Aggregate annual maturities of long-term debt obligations
2011														14,300,000,000
2012														$ 38,000,000,000