SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 6) (USD $)	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Cash Flows Between Transferor and Transferee
Gains recognized on the securitization					$ 0
U.S. government-sponsored agency guaranteed | Citicorp
Cash Flows Between Transferor and Transferee
Proceeds from new securitizations	6,200,000,000		15,400,000,000		19,400,000,000		54,200,000,000
Contractual servicing fees received	100,000,000		100,000,000		300,000,000		300,000,000
Gains recognized on the securitization	16,000,000		3,000,000		28,000,000		147,000,000
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Weighted average discount rate, date of sale or securitization (as a percent)	12.30%		10.00%		11.10%		10.00%
Weighted average constant prepayment rate, date of sale or securitization (as a percent)	5.80%		4.50%		5.40%		5.30%
Key assumptions used in measuring fair value related to transferor's continuing involvement
Weighted average discount rate, transferor's continuing involvement (as a percent)					8.60%				6.90%
Weighted average constant prepayment rate, transferor's continuing involvement (as a percent)					12.10%				11.10%
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	2,470,000,000				2,470,000,000				2,519,000,000
Carrying value of retained interests, impact of 10% adverse change in discount rate	(78,000,000)				(78,000,000)				(76,000,000)
Carrying value of retained interests, impact of 20% adverse change in discount rate	(152,000,000)				(152,000,000)				(148,000,000)
Carrying value of retained interests, impact of 10% adverse change in constant prepayment rate	(81,000,000)				(81,000,000)				(96,000,000)
Carrying value of retained interests, impact of 20% adverse change in constant prepayment rate	(157,000,000)				(157,000,000)				(187,000,000)
U.S. government-sponsored agency guaranteed | Citicorp | Low end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)	0.00%		0.80%		0.00%		0.80%
Constant prepayment rate, date of sale or securitization (as a percent)	4.60%		2.40%		0.00%		2.40%
Weighted average life, date of sale or securitization	5 years 2 months 12 days		5 years 3 months 18 days		0 years		1 month 6 days
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					0.00%				0.10%
Constant prepayment rate, transferor's continuing involvement (as a percent)					5.40%				6.20%
Weighted average life, transferor's continuing involvement					1 month 6 days				2 years 1 month 6 days
U.S. government-sponsored agency guaranteed | Citicorp | High end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)	14.70%		12.20%		14.70%		12.40%
Constant prepayment rate, date of sale or securitization (as a percent)	18.10%		19.00%		18.10%		21.40%
Weighted average life, date of sale or securitization	8 years 10 months 24 days		8 years 4 months 24 days		9 years 8 months 12 days		11 years 9 months 18 days
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					22.00%				20.90%
Constant prepayment rate, transferor's continuing involvement (as a percent)					36.40%				30.40%
Weighted average life, transferor's continuing involvement					19 years				14 years 1 month 6 days
U.S. government-sponsored agency guaranteed | Citi Holdings
Cash Flows Between Transferor and Transferee
Proceeds from new securitizations	100,000,000		100,000,000		200,000,000		100,000,000
Contractual servicing fees received			100,000,000		100,000,000		200,000,000
Gains recognized on the securitization	10,000,000		7,000,000		30,000,000		14,000,000
Key assumptions used in measuring fair value related to transferor's continuing involvement
Weighted average discount rate, transferor's continuing involvement (as a percent)					19.10%				9.50%
Weighted average constant prepayment rate, transferor's continuing involvement (as a percent)					27.70%				20.00%
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	238,000,000				238,000,000				585,000,000
Carrying value of retained interests, impact of 10% adverse change in discount rate	(7,000,000)				(7,000,000)				(16,000,000)
Carrying value of retained interests, impact of 20% adverse change in discount rate	(14,000,000)				(14,000,000)				(32,000,000)
Carrying value of retained interests, impact of 10% adverse change in constant prepayment rate	(6,000,000)				(6,000,000)				(33,000,000)
Carrying value of retained interests, impact of 20% adverse change in constant prepayment rate	(12,000,000)				(12,000,000)				(65,000,000)
U.S. government-sponsored agency guaranteed | Citi Holdings | Low end of range
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					4.40%				0.00%
Constant prepayment rate, transferor's continuing involvement (as a percent)					18.10%				9.60%
Weighted average life, transferor's continuing involvement					4 years 1 month 6 days				2 years 3 months 18 days
U.S. government-sponsored agency guaranteed | Citi Holdings | High end of range
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					32.40%				49.30%
Constant prepayment rate, transferor's continuing involvement (as a percent)					28.00%				26.20%
Weighted average life, transferor's continuing involvement					7 years 2 months 12 days				7 years 7 months 6 days
Mortgage securitizations - Non-agency-sponsored | Citicorp
Cash Flows Between Transferor and Transferee
Proceeds from new securitizations	1,700,000,000		2,000,000,000		6,900,000,000		5,000,000,000
Gains recognized on the securitization	9,000,000		13,000,000		38,000,000		45,000,000
Senior interests | Citicorp
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)	0.00%	[1]	3.90%	[1]
Weighted average discount rate, date of sale or securitization (as a percent)	0.00%	[1]	3.90%	[1]	3.80%	[1]	3.40%	[1]
Constant prepayment rate, date of sale or securitization (as a percent)	0.00%	[1]	5.40%	[1]	0.00%
Weighted average constant prepayment rate, date of sale or securitization (as a percent)	0.00%	[1]	5.40%	[1]	0.00%	[1]	7.20%	[1]
Anticipated net credit losses, date of sale or securitization (as a percent)	0.00%	[1],[2]	47.80%	[1]	40.00%
Weighted average anticipated net credit losses, date of sale or securitization (as a percent)	0.00%	[1]	47.80%	[1]	40.00%	[1]	49.30%	[1]
Key assumptions used in measuring fair value related to transferor's continuing involvement
Weighted average discount rate, transferor's continuing involvement (as a percent)					6.00%	[1]			5.50%	[1]
Weighted average constant prepayment rate, transferor's continuing involvement (as a percent)					19.80%	[1]			6.40%	[1]
Weighted average anticipated credit losses, transferor's continuing involvement (as a percent)					27.50%	[1]			49.50%	[1]
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	158,000,000	[1]			158,000,000	[1]			293,000,000	[1]
Carrying value of retained interests, impact of 10% adverse change in discount rate	(3,000,000)	[1]			(3,000,000)	[1]			(6,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in discount rate	(5,000,000)	[1]			(5,000,000)	[1]			(11,000,000)	[1]
Carrying value of retained interests, impact of 10% adverse change in constant prepayment rate	(1,000,000)	[1]			(1,000,000)	[1]			(1,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in constant prepayment rate	(2,000,000)	[1]			(2,000,000)	[1]			(2,000,000)	[1]
Carrying value of retained interests, impact of 10% adverse change in anticipated net credit losses	(2,000,000)	[1]			(2,000,000)	[1]			(2,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in anticipated net credit losses	(2,000,000)	[1]			(2,000,000)	[1]			(3,000,000)	[1]
Senior interests | Citicorp | Low end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					1.40%	[1]	2.30%	[1]
Constant prepayment rate, date of sale or securitization (as a percent)							5.40%	[1]
Anticipated net credit losses, date of sale or securitization (as a percent)							47.20%	[1]
Weighted average life, date of sale or securitization			7 years	[1]	2 years 7 months 6 days	[1]	2 years 10 months 24 days	[1]
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					1.00%	[1]			0.50%	[1]
Constant prepayment rate, transferor's continuing involvement (as a percent)					3.10%	[1]			1.30%	[1]
Anticipated credit losses, transferor's continuing involvement (as a percent)					0.00%	[1],[2]			0.10%	[1],[2]
Weighted average life, transferor's continuing involvement					8 months 12 days	[1]			0 years	[1]
Senior interests | Citicorp | High end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					4.60%	[1]	4.30%	[1]
Constant prepayment rate, date of sale or securitization (as a percent)							10.00%	[1]
Anticipated net credit losses, date of sale or securitization (as a percent)							53.00%	[1]
Weighted average life, date of sale or securitization			7 years	[1]	8 years 7 months 6 days	[1]	9 years 8 months 12 days	[1]
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					17.30%	[1]			17.40%	[1]
Constant prepayment rate, transferor's continuing involvement (as a percent)					100.00%	[1]			100.00%	[1]
Anticipated credit losses, transferor's continuing involvement (as a percent)					40.00%	[1],[2]			80.00%	[1],[2]
Weighted average life, transferor's continuing involvement					11 years 10 months 24 days	[1]			11 years 10 months 24 days	[1]
Senior interests | Citi Holdings
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					35.80%	[1]			9.90%	[3]
Weighted average discount rate, transferor's continuing involvement (as a percent)					35.80%	[1]			9.90%	[3]
Constant prepayment rate, transferor's continuing involvement (as a percent)					11.70%	[1]
Weighted average constant prepayment rate, transferor's continuing involvement (as a percent)					11.70%	[1]			15.60%	[3]
Anticipated credit losses, transferor's continuing involvement (as a percent)					0.20%	[1]			0.30%	[3]
Weighted average anticipated credit losses, transferor's continuing involvement (as a percent)					0.20%	[1]			0.30%	[3]
Weighted average life, transferor's continuing involvement					3 years 4 months	[1]			5 years 2 months	[3]
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	24,000,000				24,000,000				50,000,000	[1]
Carrying value of retained interests, impact of 10% adverse change in discount rate	(3,000,000)				(3,000,000)				(3,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in discount rate	(5,000,000)				(5,000,000)				(5,000,000)	[1]
Carrying value of retained interests, impact of 10% adverse change in constant prepayment rate	(2,000,000)				(2,000,000)				(3,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in constant prepayment rate	(4,000,000)				(4,000,000)				(6,000,000)	[1]
Carrying value of retained interests, impact of 10% adverse change in anticipated net credit losses	(4,000,000)				(4,000,000)				(5,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in anticipated net credit losses	(8,000,000)				(8,000,000)				(11,000,000)	[1]
Senior interests | Citi Holdings | Low end of range
Key assumptions used in measuring fair value related to transferor's continuing involvement
Constant prepayment rate, transferor's continuing involvement (as a percent)									12.30%	[1]
Senior interests | Citi Holdings | High end of range
Key assumptions used in measuring fair value related to transferor's continuing involvement
Constant prepayment rate, transferor's continuing involvement (as a percent)									27.30%	[1]
Subordinated interests | Citicorp
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Weighted average discount rate, date of sale or securitization (as a percent)	8.70%	[1]	6.10%	[1]	7.80%	[1]	7.60%	[1]
Weighted average constant prepayment rate, date of sale or securitization (as a percent)	1.70%	[1]	6.80%	[1]	3.20%	[1]	6.90%	[1]
Weighted average anticipated net credit losses, date of sale or securitization (as a percent)	35.60%	[1]	29.60%	[1]	43.10%	[1]	49.30%	[1]
Key assumptions used in measuring fair value related to transferor's continuing involvement
Weighted average discount rate, transferor's continuing involvement (as a percent)					8.70%	[1]			11.20%	[1]
Weighted average constant prepayment rate, transferor's continuing involvement (as a percent)					6.40%	[1]			7.40%	[1]
Weighted average anticipated credit losses, transferor's continuing involvement (as a percent)					15.20%	[1]			52.80%	[1]
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	502,000,000	[1]			502,000,000	[1]			429,000,000	[1]
Carrying value of retained interests, impact of 10% adverse change in discount rate	(30,000,000)	[1]			(30,000,000)	[1]			(25,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in discount rate	(58,000,000)	[1]			(58,000,000)	[1]			(48,000,000)	[1]
Carrying value of retained interests, impact of 10% adverse change in constant prepayment rate	(8,000,000)	[1]			(8,000,000)	[1]			(7,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in constant prepayment rate	(17,000,000)	[1]			(17,000,000)	[1]			(14,000,000)	[1]
Carrying value of retained interests, impact of 10% adverse change in anticipated net credit losses	(10,000,000)	[1]			(10,000,000)	[1]			(7,000,000)	[1]
Carrying value of retained interests, impact of 20% adverse change in anticipated net credit losses	(17,000,000)	[1]			(17,000,000)	[1]			(14,000,000)	[1]
Subordinated interests | Citicorp | Low end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)	6.70%	[1]	0.10%	[1]	2.60%	[1]	0.10%	[1]
Constant prepayment rate, date of sale or securitization (as a percent)	0.50%		0.10%	[1]	0.50%	[1]	0.10%	[1]
Anticipated net credit losses, date of sale or securitization (as a percent)	8.90%		0.10%	[1],[2]	8.90%	[1],[2]	0.10%	[1],[2]
Weighted average life, date of sale or securitization	6 years 8 months 12 days	[1]	10 years	[1]	3 years	[1]	2 years 6 months	[1]
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					1.60%	[1]			2.10%	[1]
Constant prepayment rate, transferor's continuing involvement (as a percent)					0.50%	[1]			1.40%	[1]
Anticipated credit losses, transferor's continuing involvement (as a percent)					1.60%	[1],[2]			25.50%	[1],[2]
Weighted average life, transferor's continuing involvement					10 months 24 days	[1]			0 years	[1]
Subordinated interests | Citicorp | High end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)	9.00%	[1]	9.80%	[1]	9.10%	[1]	19.20%	[1]
Constant prepayment rate, date of sale or securitization (as a percent)	8.90%		11.20%	[1]	8.90%	[1]	11.20%	[1]
Anticipated net credit losses, date of sale or securitization (as a percent)	40.00%		49.00%	[1],[2]	58.50%	[1],[2]	89.00%	[1],[2]
Weighted average life, date of sale or securitization	7 years 3 months 18 days	[1]	10 years 2 months 12 days	[1]	14 years 6 months	[1]	16 years 6 months	[1]
Key assumptions used in measuring fair value related to transferor's continuing involvement
Discount rate, transferor's continuing involvement (as a percent)					18.20%	[1]			19.60%	[1]
Constant prepayment rate, transferor's continuing involvement (as a percent)					16.00%	[1]			23.10%	[1]
Anticipated credit losses, transferor's continuing involvement (as a percent)					40.00%	[1],[2]			81.90%	[1],[2]
Weighted average life, transferor's continuing involvement					25 years 3 months 18 days	[1]			26 years	[1]
Collateralized debt obligations (CDOs) | Citi Holdings
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	6,000,000				6,000,000				19,000,000
Carrying value of retained interests, impact of 10% adverse change in discount rate	(1,000,000)				(1,000,000)				(1,000,000)
Carrying value of retained interests, impact of 20% adverse change in discount rate	(2,000,000)				(2,000,000)				(2,000,000)
Collateralized debt obligations (CDOs) | Citi Holdings | Low end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					44.40%				44.30%
Collateralized debt obligations (CDOs) | Citi Holdings | High end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					48.90%				48.70%
Collateralized loan obligations (CLOs) | Low end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					1.50%				1.50%
Collateralized loan obligations (CLOs) | High end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					1.60%				1.60%
Collateralized loan obligations (CLOs) | Citicorp
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	1,542,000,000				1,542,000,000				1,333,000,000
Carrying value of retained interests, impact of 10% adverse change in discount rate	(10,000,000)				(10,000,000)				(7,000,000)
Carrying value of retained interests, impact of 20% adverse change in discount rate	(20,000,000)				(20,000,000)				(14,000,000)
Collateralized loan obligations (CLOs) | Citi Holdings
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	8,000,000				8,000,000				31,000,000
Collateralized loan obligations (CLOs) | Citi Holdings | Low end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					4.50%				4.50%
Collateralized loan obligations (CLOs) | Citi Holdings | High end of range
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)					5.00%				5.00%
Asset-backed securities | Citicorp
Cash Flows Between Transferor and Transferee
Proceeds from new securitizations	0				500,000,000
Key assumptions used in measuring fair value of retained interests at date of sale or securitization of mortgage receivables
Discount rate, date of sale or securitization (as a percent)									3.00%
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	0				0				1,316,000,000
Carrying value of retained interests, impact of 10% adverse change in discount rate	0				0				(11,000,000)
Carrying value of retained interests, impact of 20% adverse change in discount rate	0				0				(23,000,000)
Asset-backed securities | Citi Holdings
Sensitivity analysis of fair value of interests continued to be held by transferor
Carrying value of retained interests	0				0				95,000,000
Carrying value of retained interests, impact of 10% adverse change in discount rate	0				0				0
Carrying value of retained interests, impact of 20% adverse change in discount rate	$ 0				$ 0				$ 0

[1] Disclosure of non-agency-sponsored mortgages as senior and subordinated interests is indicative of the interests’ position in the capital structure of the securitization.

[2] Anticipated net credit losses represent estimated loss severity associated with defaulted mortgage loans underlying the mortgage securitizations disclosed above. Anticipated net credit losses, in this instance, do not represent total credit losses incurred to date, nor do they represent credit losses expected on retained interests in mortgage securitizations.

[3] Citi Holdings held no subordinated interests in mortgage securitizations as of September 30, 2014 and December 31, 2013.