SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 3) (USD $)	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	$ 26,505,000,000	$ 28,701,000,000	$ 27,842,000,000	$ 27,972,000,000
Trading account assets	307,050,000,000	291,734,000,000
Investments	297,323,000,000	293,413,000,000
Total loans, net	619,002,000,000	617,127,000,000
Other assets	147,180,000,000	148,911,000,000
Total assets	1,944,423,000,000	1,873,878,000,000
Short-term borrowings	55,611,000,000	54,441,000,000
Long-term debt	311,079,000,000	323,505,000,000
Other liabilities	69,068,000,000	69,272,000,000
Consolidated VIEs
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	478,000,000	536,000,000
Trading account assets	562,000,000	567,000,000
Investments	7,599,000,000	10,582,000,000
Total loans, net	108,592,000,000	119,055,000,000
Other assets	807,000,000	859,000,000
Total assets	118,038,000,000	131,599,000,000
Short-term borrowings	20,024,000,000	21,009,000,000
Long-term debt	45,046,000,000	50,451,000,000
Other liabilities	585,000,000	587,000,000
Total Consolidated Liabilities	67,700,000,000	74,300,000,000
Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	6,200,000,000	6,500,000,000
Investments	7,200,000,000	8,200,000,000
Total loans, net	11,300,000,000	10,400,000,000
Other assets	2,600,000,000	2,600,000,000
Total assets	27,300,000,000	27,700,000,000
Long-term debt	200,000,000	200,000,000
Total Liabilities	200,000,000	200,000,000
Citicorp
Variable Interest Entity
Total assets	1,424,000,000,000	1,365,000,000,000
Citicorp | Consolidated VIEs
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	200,000,000	200,000,000
Trading account assets	500,000,000	400,000,000
Investments	7,600,000,000	10,600,000,000
Total loans, net	98,800,000,000	109,000,000,000
Other assets	500,000,000	500,000,000
Total assets	107,600,000,000	120,700,000,000
Short-term borrowings	22,000,000,000	22,500,000,000
Long-term debt	38,800,000,000	44,800,000,000
Other liabilities	400,000,000	400,000,000
Total Consolidated Liabilities	61,200,000,000	67,700,000,000
Citicorp | Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	5,700,000,000	5,500,000,000
Investments	3,700,000,000	3,800,000,000
Total loans, net	10,100,000,000	8,800,000,000
Other assets	1,700,000,000	1,600,000,000
Total assets	21,200,000,000	19,700,000,000
Long-term debt	200,000,000	200,000,000
Total Liabilities	200,000,000	200,000,000
Citi Holdings
Variable Interest Entity
Total assets	209,000,000,000	225,000,000,000
Citi Holdings | Consolidated VIEs
Variable Interest Entity
Cash and due from banks (including segregated cash and other deposits)	300,000,000	400,000,000
Trading account assets	100,000,000	100,000,000
Total loans, net	9,700,000,000	10,100,000,000
Other assets	300,000,000	300,000,000
Total assets	10,400,000,000	10,900,000,000
Short-term borrowings		800,000,000
Long-term debt	6,300,000,000	5,600,000,000
Other liabilities	200,000,000	200,000,000
Total Consolidated Liabilities	6,500,000,000	6,600,000,000
Citi Holdings | Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	500,000,000	1,000,000,000
Investments	3,500,000,000	4,400,000,000
Total loans, net	1,200,000,000	1,600,000,000
Other assets	900,000,000	1,000,000,000
Total assets	$ 6,100,000,000	$ 8,000,000,000