DEBT (Details 2) (USD $)									3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Junior subordinated notes relating to trust preferred securities	Dec. 31, 2012 Junior subordinated notes relating to trust preferred securities	Mar. 31, 2013 Citigroup Parent Company	Dec. 31, 2012 Citigroup Parent Company	Mar. 31, 2013 Bank	Dec. 31, 2012 Bank	Mar. 31, 2013 Citigroup Global Markets Holdings Inc. (CGMHI) Revolving line of credit facility	Mar. 31, 2013 Non-bank	Dec. 31, 2012 Non-bank	Mar. 31, 2013 Citigroup Funding Inc. (CFI)	Dec. 31, 2012 Citigroup Funding Inc. (CFI)
Long-Term Debt:
Total long-term debt	$ 234,326,000,000	$ 239,463,000,000	$ 9,615,000,000	$ 10,110,000,000	$ 173,750,000,000	$ 176,553,000,000	$ 49,421,000,000	$ 51,234,000,000		$ 11,155,000,000	$ 11,676,000,000
Collateralized long-term advances from Federal Home Loan Bank							16,300,000,000	16,300,000,000
Carrying value of Principal-Protected Trust Securities												196,000,000	186,000,000
Amount drawn down on long-term financing facilities with unaffiliated banks									300,000,000
Notice period banks are required to give CGMHI prior to terminating financing facilities									1 year
Trust assets	$ 0