CONDENSED CONSOLIDATING FINANCIAL STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								9 Months Ended
	Sep. 30, 2012		Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2011		Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2012		Sep. 30, 2011
Condensed Consolidating Statements of Income:
Interest revenue	$ 16,934				$ 18,145				$ 51,360		$ 54,886
Interest expense	5,021				6,031				15,907		18,522
Net interest revenue	11,913				12,114				35,453		36,364
Commissions and fees	3,304				3,043				9,521		9,968
Principal transactions	976				2,103				4,547		7,886
Other income	(977)	[1]			1,349	[1]			(296)	[1]	1,933	[1]
Total non-interest revenues	2,038				8,717				16,546		24,815
Total revenues, net of interest expense	13,951				20,831				51,999		61,179
Provisions for credit losses and for benefits and claims	2,695				3,351				8,520		9,922
Compensation and benefits	6,132				6,223				18,644		19,301
Other expense	6,088				6,237				18,029		18,421
Total operating expenses	12,220				12,460				36,673		37,722
Income (loss) before taxes and equity in undistributed income of subsidiaries	(964)				5,020				6,806		13,535
Provision (benefit) for income taxes	(1,488)				1,278				233		3,430
Income from continuing operations	524				3,742				6,573		10,105
Income (loss) from discontinued operations, net of taxes	(31)				1				(37)		112
Net income before attribution of noncontrolling interests	493				3,743				6,536		10,217
Net income (loss) attributable to noncontrolling interests	25				(28)				191		106
Citigroup's net income	468				3,771				6,345		10,111
Comprehensive income (loss)
Net income before attribution of noncontrolling interests	493				3,743				6,536		10,217
Citigroup's other comprehensive income (loss)	2,183		(1,014)	1,053	(4,822)		1,762	2,293	2,222		(767)
Other comprehensive income (loss) attributable to noncontrolling interests	48				(115)				59		(62)
Total comprehensive income (loss) before attribution of noncontrolling interests	2,724				(1,194)				8,817		9,388
Total comprehensive income (loss) attributable to noncontrolling interests	73				(143)				250		44
Citigroup's comprehensive income (loss)	2,651				(1,051)				8,567		9,344
Citigroup Parent Company
Condensed Consolidating Statements of Income:
Dividends from subsidiaries	2,800				3,200				7,680		10,370
Interest revenue	4				50				122		155
Interest revenue-intercompany	767				827				2,515		2,590
Interest expense	1,678				2,006				5,440		6,164
Interest expense-intercompany	(100)				(120)				(328)		(401)
Net interest revenue	(807)				(1,009)				(2,475)		(3,018)
Principal transactions	62				(44)				84		9
Principal transactions-intercompany	9								15		1
Other income	(642)				(3,405)				(138)		(4,823)
Other income-intercompany	762				3,823				499		5,090
Total non-interest revenues	191				374				460		277
Total revenues, net of interest expense	2,184				2,565				5,665		7,629
Compensation and benefits	32				(15)				86		51
Compensation and benefits-intercompany	2				1				6		5
Other expense	239				176				839		753
Other expense-intercompany	40				100				223		302
Total operating expenses	313				262				1,154		1,111
Income (loss) before taxes and equity in undistributed income of subsidiaries	1,871				2,303				4,511		6,518
Provision (benefit) for income taxes	(975)				(300)				(1,224)		(1,633)
Equity in undistributed income of subsidiaries	(2,378)				1,168				610		1,960
Income from continuing operations	468				3,771				6,345		10,111
Net income before attribution of noncontrolling interests	468				3,771				6,345		10,111
Citigroup's net income	468				3,771				6,345		10,111
Comprehensive income (loss)
Net income before attribution of noncontrolling interests	468				3,771				6,345		10,111
Citigroup's other comprehensive income (loss)	2,183				(4,822)				2,222		(767)
Total comprehensive income (loss) before attribution of noncontrolling interests	2,651				(1,051)				8,567		9,344
Citigroup's comprehensive income (loss)	2,651				(1,051)				8,567		9,344
Citigroup Funding Inc. (CFI)
Condensed Consolidating Statements of Income:
Interest revenue	22								36
Interest revenue-intercompany	252				661				884		1,854
Interest expense	252				558				893		1,595
Interest expense-intercompany	(47)				(16)				(350)		285
Net interest revenue	69				119				377		(26)
Principal transactions	(972)				1,534				(1,869)		1,997
Principal transactions-intercompany	542				(740)				772		(1,031)
Other income	50				(84)				54		(73)
Other income-intercompany	(121)				156				(189)		64
Total non-interest revenues	(501)				866				(1,232)		957
Total revenues, net of interest expense	(432)				985				(855)		931
Other expense									1		1
Other expense-intercompany	1				5				3		7
Total operating expenses	1				5				4		8
Income (loss) before taxes and equity in undistributed income of subsidiaries	(433)				980				(859)		923
Provision (benefit) for income taxes	(161)				395				(324)		324
Income from continuing operations	(272)				585				(535)		599
Net income before attribution of noncontrolling interests	(272)				585				(535)		599
Citigroup's net income	(272)				585				(535)		599
Comprehensive income (loss)
Net income before attribution of noncontrolling interests	(272)				585				(535)		599
Total comprehensive income (loss) before attribution of noncontrolling interests	(272)				585				(535)		599
Citigroup's comprehensive income (loss)	(272)				585				(535)		599
Other Citigroup Subsidiaries, eliminations and income from discontinued operations
Condensed Consolidating Statements of Income:
Dividends from subsidiaries	(2,800)				(3,200)				(7,680)		(10,370)
Interest revenue	16,908				18,095				51,202		54,731
Interest revenue-intercompany	(1,019)				(1,488)				(3,399)		(4,444)
Interest expense	3,091				3,467				9,574		10,763
Interest expense-intercompany	147				136				678		116
Net interest revenue	12,651				13,004				37,551		39,408
Commissions and fees	3,304				3,043				9,521		9,968
Principal transactions	1,886				613				6,332		5,880
Principal transactions-intercompany	(551)				740				(787)		1,030
Other income	(1,650)				7,060				2,562		11,857
Other income-intercompany	(641)				(3,979)				(310)		(5,154)
Total non-interest revenues	2,348				7,477				17,318		23,581
Total revenues, net of interest expense	12,199				17,281				47,189		52,619
Provisions for credit losses and for benefits and claims	2,695				3,351				8,520		9,922
Compensation and benefits	6,100				6,238				18,558		19,250
Compensation and benefits-intercompany	(2)				(1)				(6)		(5)
Other expense	5,849				6,061				17,189		17,667
Other expense-intercompany	(41)				(105)				(226)		(309)
Total operating expenses	11,906				12,193				35,515		36,603
Income (loss) before taxes and equity in undistributed income of subsidiaries	(2,402)				1,737				3,154		6,094
Provision (benefit) for income taxes	(352)				1,183				1,781		4,739
Equity in undistributed income of subsidiaries	2,378				(1,168)				(610)		(1,960)
Income from continuing operations	328				(614)				763		(605)
Income (loss) from discontinued operations, net of taxes	(31)				1				(37)		112
Net income before attribution of noncontrolling interests	297				(613)				726		(493)
Net income (loss) attributable to noncontrolling interests	25				(28)				191		106
Citigroup's net income	272				(585)				535		(599)
Comprehensive income (loss)
Net income before attribution of noncontrolling interests	297				(613)				726		(493)
Other comprehensive income (loss) attributable to noncontrolling interests	48				(115)				59		(62)
Total comprehensive income (loss) before attribution of noncontrolling interests	345				(728)				785		(555)
Total comprehensive income (loss) attributable to noncontrolling interests	73				(143)				250		44
Citigroup's comprehensive income (loss)	$ 272				$ (585)				$ 535		$ (599)

[1] Other revenue for the third quarter of 2012 includes a $1,344 million loss related to the sale of a 14% interest in MSSB. Additionally, Other revenue for the nine months of 2012 included the recognition of a $424 million loss related to the sale of Citi's 10.1% stake in Akbank.