SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 3) (USD $)	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Dec. 31, 2009
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	$ 27,766,000,000	$ 27,972,000,000	$ 24,709,000,000	$ 25,472,000,000
Trading account assets	322,349,000,000	317,272,000,000
Investments	309,574,000,000	318,164,000,000
Total loans, net	613,138,000,000	608,139,000,000
Other assets	164,932,000,000	163,778,000,000
Total assets	1,956,626,000,000	1,913,902,000,000
Long-term debt	352,458,000,000	381,183,000,000
Consolidated VIEs | Citicorp
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	200,000,000	200,000,000
Trading account assets	600,000,000	4,900,000,000
Investments	7,800,000,000	7,900,000,000
Total loans, net	79,600,000,000	85,300,000,000
Other assets	600,000,000	100,000,000
Total assets	88,800,000,000	98,400,000,000
Short-term borrowings	21,800,000,000	23,100,000,000
Long-term debt	35,800,000,000	47,600,000,000
Other liabilities	100,000,000	600,000,000
Total Liabilities	57,700,000,000	71,300,000,000
Citicorp | Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	3,600,000,000	3,600,000,000
Investments	3,400,000,000	3,800,000,000
Total loans, net	9,900,000,000	7,300,000,000
Other assets	2,300,000,000	2,700,000,000
Total assets	19,200,000,000	17,400,000,000
Long-term debt	300,000,000	400,000,000
Total Liabilities	300,000,000	400,000,000
Consolidated VIEs | Citi Holdings
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	800,000,000	600,000,000
Trading account assets	200,000,000	1,600,000,000
Investments	200,000,000
Total loans, net	37,800,000,000	44,700,000,000
Other assets	1,100,000,000	600,000,000
Total assets	40,100,000,000	47,500,000,000
Short-term borrowings	800,000,000	2,200,000,000
Long-term debt	19,500,000,000	22,100,000,000
Other liabilities	400,000,000	200,000,000
Total Liabilities	20,700,000,000	24,500,000,000
Citi Holdings | Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	1,500,000,000	2,700,000,000
Investments	5,500,000,000	5,900,000,000
Total loans, net	3,000,000,000	5,000,000,000
Other assets	1,700,000,000	2,000,000,000
Total assets	11,700,000,000	15,600,000,000
Long-term debt		500,000,000
Total Liabilities		500,000,000
Consolidated VIEs
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	996,000,000	799,000,000
Trading account assets	843,000,000	6,509,000,000
Investments	7,946,000,000	7,946,000,000
Total loans, net	117,488,000,000	129,959,000,000
Other assets	1,708,000,000	680,000,000
Total assets	128,981,000,000	145,893,000,000
Short-term borrowings	22,600,000,000	25,300,000,000
Long-term debt	55,254,000,000	69,710,000,000
Other liabilities	500,000,000	800,000,000
Total Liabilities	78,400,000,000	95,800,000,000
Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	5,100,000,000	6,300,000,000
Investments	8,900,000,000	9,700,000,000
Total loans, net	12,900,000,000	12,300,000,000
Other assets	4,000,000,000	4,700,000,000
Total assets	30,900,000,000	33,000,000,000
Long-term debt	300,000,000	900,000,000
Total Liabilities	$ 300,000,000	$ 900,000,000