SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 8) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Variable Interest Entity
Total unconsolidated VIE assets	$ 451,567,000,000		$ 451,567,000,000		$ 499,481,000,000
Maximum exposure to unconsolidated VIEs	39,175,000,000		39,175,000,000		45,971,000,000
Citicorp
Variable Interest Entity
Total unconsolidated VIE assets	332,231,000,000		332,231,000,000		354,493,000,000
Maximum exposure to unconsolidated VIEs	35,413,000,000		35,413,000,000		41,644,000,000
Citicorp | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	37,600,000,000		37,600,000,000		40,200,000,000
Maximum exposure to unconsolidated VIEs	18,200,000,000		18,200,000,000		17,100,000,000
Cash flows received on retained interest and other net cash flows	300,000,000		600,000,000
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	1,241,000,000		1,241,000,000		1,726,000,000
Citi Holdings
Variable Interest Entity
Total unconsolidated VIE assets	119,336,000,000		119,336,000,000		144,988,000,000
Maximum exposure to unconsolidated VIEs	3,762,000,000		3,762,000,000		4,327,000,000
Citi Holdings | Collateralized debt obligations (CDOs)
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	16,000,000		16,000,000		16,000,000
Citi Holdings | Collateralized loan obligations (CLOs)
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	1,167,000,000		1,167,000,000		428,000,000
Citi Holdings | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	3,400,000,000		3,400,000,000		4,200,000,000
Maximum exposure to unconsolidated VIEs	900,000,000		900,000,000		1,200,000,000
Cash flows received on retained interest and other net cash flows	200,000,000	400,000,000	200,000,000	1,300,000,000
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	107,000,000		107,000,000		339,000,000
Commercial and other real estate | Citicorp | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	12,500,000,000		12,500,000,000		16,100,000,000
Maximum exposure to unconsolidated VIEs	3,200,000,000		3,200,000,000		3,100,000,000
Commercial and other real estate | Citi Holdings | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	800,000,000		800,000,000		900,000,000
Maximum exposure to unconsolidated VIEs	300,000,000		300,000,000		300,000,000
Corporate loans | Citicorp | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	2,200,000,000		2,200,000,000		2,000,000,000
Maximum exposure to unconsolidated VIEs	1,800,000,000		1,800,000,000		1,600,000,000
Corporate loans | Citi Holdings | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	100,000,000		100,000,000		400,000,000
Maximum exposure to unconsolidated VIEs	100,000,000		100,000,000		300,000,000
Hedge funds and equities | Citicorp | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets					600,000,000
Maximum exposure to unconsolidated VIEs					400,000,000
Airplanes, ships and other assets | Citicorp | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	22,900,000,000		22,900,000,000		21,500,000,000
Maximum exposure to unconsolidated VIEs	13,200,000,000		13,200,000,000		12,000,000,000
Airplanes, ships and other assets | Citi Holdings | Asset-based financing
Variable Interest Entity
Total unconsolidated VIE assets	2,500,000,000		2,500,000,000		2,900,000,000
Maximum exposure to unconsolidated VIEs	$ 500,000,000		$ 500,000,000		$ 600,000,000