SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details) (USD $)					3 Months Ended																													3 Months Ended	6 Months Ended	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Citicorp	Dec. 31, 2012 Citicorp	Mar. 31, 2013 Citicorp Credit card securitizations	Dec. 31, 2013 Citicorp Credit card securitizations	Dec. 31, 2012 Citicorp Credit card securitizations	Dec. 31, 2013 Citicorp U.S. government-sponsored agency guaranteed	Dec. 31, 2012 Citicorp U.S. government-sponsored agency guaranteed	Dec. 31, 2013 Citicorp Non-agency-sponsored mortgages	Dec. 31, 2012 Citicorp Non-agency-sponsored mortgages	Dec. 31, 2013 Citicorp Citi-administered asset-backed commercial paper conduits (ABCP)	Dec. 31, 2012 Citicorp Citi-administered asset-backed commercial paper conduits (ABCP)	Dec. 31, 2013 Citicorp Collateralized debt obligations (CDOs)	Dec. 31, 2012 Citicorp Collateralized debt obligations (CDOs)	Dec. 31, 2013 Citicorp Collateralized loan obligations (CLOs)	Dec. 31, 2012 Citicorp Collateralized loan obligations (CLOs)	Dec. 31, 2013 Citicorp Asset-based financing	Dec. 31, 2012 Citicorp Asset-based financing	Dec. 31, 2013 Citicorp Municipal securities tender option bond trusts (TOBs)	Dec. 31, 2012 Citicorp Municipal securities tender option bond trusts (TOBs)	Dec. 31, 2013 Citicorp Municipal investments	Dec. 31, 2012 Citicorp Municipal investments	Dec. 31, 2013 Citicorp Client intermediation	Dec. 31, 2012 Citicorp Client intermediation	Dec. 31, 2013 Citicorp Investment funds	Dec. 31, 2012 Citicorp Investment funds	Dec. 31, 2013 Citicorp Trust preferred securities	Dec. 31, 2012 Citicorp Trust preferred securities	Dec. 31, 2013 Citicorp Other	Dec. 31, 2012 Citicorp Other	Dec. 31, 2013 Citicorp Mortgage-backed securities	Dec. 31, 2012 Citicorp Mortgage-backed securities	Mar. 31, 2013 Citibank Credit Card Master Trust (Master Trust) Credit card securitizations	Dec. 31, 2013 Citibank Credit Card Master Trust (Master Trust) Credit card securitizations	Mar. 31, 2013 Citibank OMNI Master Trust (Omni Trust) Credit card securitizations	Dec. 31, 2013 Citi Holdings	Dec. 31, 2012 Citi Holdings	Dec. 31, 2013 Citi Holdings Credit card securitizations	Dec. 31, 2012 Citi Holdings Credit card securitizations	Dec. 31, 2013 Citi Holdings U.S. government-sponsored agency guaranteed	Dec. 31, 2012 Citi Holdings U.S. government-sponsored agency guaranteed	Dec. 31, 2013 Citi Holdings Non-agency-sponsored mortgages	Dec. 31, 2012 Citi Holdings Non-agency-sponsored mortgages	Dec. 31, 2013 Citi Holdings Student loan securitizations	Dec. 31, 2012 Citi Holdings Student loan securitizations	Dec. 31, 2013 Citi Holdings Collateralized debt obligations (CDOs)	Dec. 31, 2012 Citi Holdings Collateralized debt obligations (CDOs)	Dec. 31, 2013 Citi Holdings Collateralized loan obligations (CLOs)	Dec. 31, 2012 Citi Holdings Collateralized loan obligations (CLOs)	Dec. 31, 2013 Citi Holdings Asset-based financing	Dec. 31, 2012 Citi Holdings Asset-based financing	Dec. 31, 2013 Citi Holdings Municipal investments	Dec. 31, 2012 Citi Holdings Municipal investments	Dec. 31, 2012 Citi Holdings Client intermediation	Dec. 31, 2013 Citi Holdings Investment funds	Dec. 31, 2012 Citi Holdings Investment funds	Dec. 31, 2013 Citi Holdings Other	Dec. 31, 2012 Citi Holdings Other
Variable Interest Entity
Total involvement with SPE assets	$ 580,408,000,000	$ 649,630,000,000	$ 467,378,000,000	$ 493,231,000,000		$ 52,229,000,000	$ 77,770,000,000	$ 239,204,000,000	$ 232,741,000,000	$ 7,711,000,000	$ 8,810,000,000	$ 31,759,000,000	$ 30,002,000,000	$ 4,204,000,000	$ 5,539,000,000	$ 16,883,000,000	$ 15,120,000,000	$ 45,884,000,000	$ 41,399,000,000	$ 12,716,000,000	$ 15,163,000,000	$ 15,962,000,000	$ 19,693,000,000	$ 1,778,000,000	$ 2,486,000,000	$ 31,787,000,000	$ 30,264,000,000	$ 4,822,000,000	$ 12,221,000,000	$ 2,439,000,000	$ 2,023,000,000						$ 113,030,000,000	$ 156,399,000,000	$ 1,867,000,000	$ 2,177,000,000	$ 73,549,000,000	$ 106,888,000,000	$ 13,193,000,000	$ 17,192,000,000	$ 1,520,000,000	$ 1,681,000,000	$ 3,625,000,000	$ 4,752,000,000	$ 2,733,000,000	$ 4,676,000,000	$ 3,508,000,000	$ 4,166,000,000	$ 7,304,000,000	$ 7,766,000,000	$ 13,000,000	$ 1,237,000,000	$ 1,083,000,000	$ 4,494,000,000	$ 6,005,000,000
Consolidated VIE / SPE assets	104,896,000,000	124,171,000,000	95,796,000,000	112,760,000,000		52,229,000,000	77,770,000,000			598,000,000	1,188,000,000	31,759,000,000	22,387,000,000					971,000,000	1,125,000,000	7,039,000,000	7,573,000,000	223,000,000	255,000,000	195,000,000	151,000,000	2,557,000,000	2,196,000,000			225,000,000	115,000,000						9,100,000,000	11,411,000,000	1,448,000,000	1,736,000,000			1,695,000,000	2,127,000,000	1,520,000,000	1,681,000,000					3,000,000	3,000,000			13,000,000			4,434,000,000	5,851,000,000
Significant unconsolidated VIE assets	475,512,000,000	525,459,000,000	371,582,000,000	380,471,000,000				239,204,000,000	232,741,000,000	7,113,000,000	7,622,000,000		7,615,000,000	4,204,000,000	5,539,000,000	16,883,000,000	15,120,000,000	44,913,000,000	40,274,000,000	5,677,000,000	7,590,000,000	15,739,000,000	19,438,000,000	1,583,000,000	2,335,000,000	29,230,000,000	28,068,000,000	4,822,000,000	12,221,000,000	2,214,000,000	1,908,000,000						103,930,000,000	144,988,000,000	419,000,000	441,000,000	73,549,000,000	106,888,000,000	11,498,000,000	15,065,000,000			3,625,000,000	4,752,000,000	2,733,000,000	4,676,000,000	3,505,000,000	4,163,000,000	7,304,000,000	7,766,000,000		1,237,000,000	1,083,000,000	60,000,000	154,000,000
Funded Exposure
Maximum exposure to loss in significant unconsolidated VIEs, debt investments	27,606,000,000	24,066,000,000	25,944,000,000	21,675,000,000				3,583,000,000	3,042,000,000	583,000,000	382,000,000			34,000,000	24,000,000	1,938,000,000	642,000,000	17,452,000,000	14,798,000,000	29,000,000	352,000,000	1,846,000,000	2,003,000,000	145,000,000	319,000,000	191,000,000				143,000,000	113,000,000						1,662,000,000	2,391,000,000			549,000,000	700,000,000	35,000,000	43,000,000			88,000,000	139,000,000	358,000,000	435,000,000	629,000,000	984,000,000	3,000,000	90,000,000
Maximum exposure to loss in significant unconsolidated VIEs, equity investments	3,379,000,000	4,174,000,000	3,111,000,000	3,883,000,000													19,000,000	74,000,000	84,000,000			2,073,000,000	3,049,000,000			264,000,000	223,000,000	51,000,000	126,000,000	649,000,000	382,000,000						268,000,000	291,000,000													3,000,000	6,000,000	204,000,000	235,000,000		61,000,000	47,000,000		3,000,000
Unfunded Exposure
Maximum exposure to loss in significant unconsolidated VIEs, funding commitments	7,484,000,000	17,263,000,000	6,287,000,000	16,015,000,000									7,615,000,000					1,132,000,000	2,081,000,000	3,881,000,000	4,628,000,000	1,173,000,000	1,669,000,000			81,000,000				20,000,000	22,000,000						1,197,000,000	1,248,000,000												13,000,000	258,000,000	243,000,000	939,000,000	992,000,000
Maximum exposure to loss in significant unconsolidated VIEs, guarantees and derivatives	586,000,000	677,000,000	309,000,000	280,000,000				36,000,000	45,000,000									195,000,000	159,000,000											78,000,000	76,000,000						277,000,000	397,000,000			77,000,000	163,000,000	2,000,000	2,000,000			87,000,000	124,000,000	111,000,000	108,000,000
Funded and Unfunded Exposure
Maximum exposure to loss in significant unconsolidated VIEs	39,055,000,000	46,180,000,000	35,651,000,000	41,853,000,000				3,619,000,000	3,087,000,000	583,000,000	382,000,000		7,615,000,000	34,000,000	24,000,000	1,938,000,000	661,000,000	18,853,000,000	17,122,000,000	3,910,000,000	4,980,000,000	5,092,000,000	6,721,000,000	145,000,000	319,000,000	536,000,000	223,000,000	51,000,000	126,000,000	890,000,000	593,000,000						3,404,000,000	4,327,000,000			626,000,000	863,000,000	37,000,000	45,000,000			175,000,000	263,000,000	469,000,000	556,000,000	890,000,000	1,233,000,000	1,146,000,000	1,317,000,000		61,000,000	47,000,000		3,000,000
Private label mortgage-backed securities, outstanding																																16,000,000,000	19,000,000,000
Amount removed from or (added in) credit card receivables					$ 27,000,000,000																													$ 12,000,000,000	$ (7,400,000,000)	$ 15,000,000,000