CONDENSED CONSOLIDATING FINANCIAL STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Condensed Consolidating Statements of Income:
Interest revenue	$ 17,034	$ 18,586	$ 34,571	$ 36,741
Interest expense	5,441	6,438	11,031	12,491
Net interest revenue	11,593	12,148	23,540	24,250
Commissions and fees	3,079	3,557	6,217	6,925
Principal transactions	1,640	2,616	3,571	5,783
Other income	2,330	2,301	4,720	3,390
Total non-interest revenues	7,049	8,474	14,508	16,098
Total revenues, net of interest expense	18,642	20,622	38,048	40,348
Provisions for credit losses and for benefits and claims	2,806	3,387	5,825	6,571
Compensation and benefits	6,127	6,669	12,512	13,078
Other expense	6,007	6,267	11,941	12,184
Total operating expenses	12,134	12,936	24,453	25,262
Income (loss) before taxes and equity in undistributed income of subsidiaries	3,702	4,299	7,770	8,515
Provision (benefit) for income taxes	715	967	1,721	2,152
Income from continuing operations	2,987	3,332	6,049	6,363
Income (loss) from discontinued operations, net of taxes	(1)	71	(6)	111
Net income before attribution of noncontrolling interests	2,986	3,403	6,043	6,474
Net income (loss) attributable to noncontrolling interests	40	62	166	134
Citigroup's net income	2,946	3,341	5,877	6,340
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	2,986	3,403	6,043	6,474
Citigroup's other comprehensive income (loss)	(1,014)	1,762	39	4,055
Other comprehensive income (loss) attributable to noncontrolling interests	(53)	24	11	53
Total comprehensive income before attribution of noncontrolling interests	1,919	5,189	6,093	10,582
Total comprehensive income (loss) attributable to noncontrolling interests	(13)	86	177	187
Citigroup's comprehensive income	1,932	5,103	5,916	10,395
Citigroup Parent Company
Condensed Consolidating Statements of Income:
Dividends from subsidiaries	3,380	6,645	4,880	7,170
Interest revenue	52	53	118	105
Interest revenue-intercompany	840	819	1,748	1,763
Interest expense	1,822	2,110	3,762	4,158
Interest expense-intercompany	(113)	(94)	(228)	(281)
Net interest revenue	(817)	(1,144)	(1,668)	(2,009)
Principal transactions	(45)	10	22	53
Principal transactions-intercompany	(4)		6	1
Other income	(761)	(1,433)	504	(1,418)
Other income-intercompany	1,204	1,442	(263)	1,267
Total non-interest revenues	394	19	269	(97)
Total revenues, net of interest expense	2,957	5,520	3,481	5,064
Compensation and benefits	(6)	22	54	66
Compensation and benefits-intercompany	2	2	4	4
Other expense	193	267	600	577
Other expense-intercompany	56	93	183	202
Total operating expenses	245	384	841	849
Income (loss) before taxes and equity in undistributed income of subsidiaries	2,712	5,136	2,640	4,215
Provision (benefit) for income taxes	(340)	(693)	(249)	(1,333)
Equity in undistributed income of subsidiaries	(106)	(2,488)	2,988	792
Income from continuing operations	2,946	3,341	5,877	6,340
Net income before attribution of noncontrolling interests	2,946	3,341	5,877	6,340
Citigroup's net income	2,946	3,341	5,877	6,340
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	2,946	3,341	5,877	6,340
Citigroup's other comprehensive income (loss)	(1,014)	1,762	39	4,055
Total comprehensive income before attribution of noncontrolling interests	1,932	5,103	5,916	10,395
Citigroup's comprehensive income	1,932	5,103	5,916	10,395
Citigroup Global Markets Holdings Inc. (CGMHI)
Condensed Consolidating Statements of Income:
Interest revenue	1,407	1,493	2,660	2,961
Interest revenue-intercompany	225	540	464	1,082
Interest expense	647	731	1,130	1,282
Interest expense-intercompany	757	762	1,388	1,573
Net interest revenue	228	540	606	1,188
Commissions and fees	997	1,274	2,087	2,422
Commissions and fees-intercompany	47	26	77	25
Principal transactions	2,027	1,687	1,967	1,516
Principal transactions-intercompany	(1,361)	(1,071)	(580)	152
Other income	42	166	213	481
Other income-intercompany	93	61	(229)	(14)
Total non-interest revenues	1,845	2,143	3,535	4,582
Total revenues, net of interest expense	2,073	2,683	4,141	5,770
Provisions for credit losses and for benefits and claims	6	(4)	11	6
Compensation and benefits	1,331	1,562	2,734	3,021
Compensation and benefits-intercompany	54	59	109	116
Other expense	580	657	1,170	1,337
Other expense-intercompany	170	102	351	181
Total operating expenses	2,135	2,380	4,364	4,655
Income (loss) before taxes and equity in undistributed income of subsidiaries	(68)	307	(234)	1,109
Provision (benefit) for income taxes	4	99	(150)	471
Income from continuing operations	(72)	208	(84)	638
Net income before attribution of noncontrolling interests	(72)	208	(84)	638
Net income (loss) attributable to noncontrolling interests	1	19	10	30
Citigroup's net income	(73)	189	(94)	608
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	(72)	208	(84)	638
Citigroup's other comprehensive income (loss)	(80)	12	(30)	36
Total comprehensive income before attribution of noncontrolling interests	(152)	220	(114)	674
Total comprehensive income (loss) attributable to noncontrolling interests	1	19	10	30
Citigroup's comprehensive income	(153)	201	(124)	644
Citigroup Funding Inc. (CFI)
Condensed Consolidating Statements of Income:
Interest revenue	7		14
Interest revenue-intercompany	290	589	632	1,193
Interest expense	259	503	641	1,037
Interest expense-intercompany	(195)	107	(303)	301
Net interest revenue	233	(21)	308	(145)
Principal transactions	111	229	(897)	463
Principal transactions-intercompany	(47)	(62)	230	(291)
Other income	(26)	(44)	4	11
Other income-intercompany	55	73	(68)	(92)
Total non-interest revenues	93	196	(731)	91
Total revenues, net of interest expense	326	175	(423)	(54)
Other expense	1		1	1
Other expense-intercompany	1	1	2	2
Total operating expenses	2	1	3	3
Income (loss) before taxes and equity in undistributed income of subsidiaries	324	174	(426)	(57)
Provision (benefit) for income taxes	118	58	(163)	(71)
Income from continuing operations	206	116	(263)	14
Net income before attribution of noncontrolling interests	206	116	(263)	14
Citigroup's net income	206	116	(263)	14
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	206	116	(263)	14
Total comprehensive income before attribution of noncontrolling interests	206	116	(263)	14
Citigroup's comprehensive income	206	116	(263)	14
CitiFinancial Credit Company (CCC)
Condensed Consolidating Statements of Income:
Interest revenue	822	1,034	1,668	2,085
Interest revenue-intercompany	22	25	47	51
Interest expense	26	23	52	52
Interest expense-intercompany	268	382	545	778
Net interest revenue	550	654	1,118	1,306
Commissions and fees	1	1	3	3
Commissions and fees-intercompany	1	28	(1)	56
Other income	123	108	29	219
Other income-intercompany	1	(3)	1	(3)
Total non-interest revenues	126	134	32	275
Total revenues, net of interest expense	676	788	1,150	1,581
Provisions for credit losses and for benefits and claims	389	376	857	773
Compensation and benefits	90	112	184	219
Compensation and benefits-intercompany	27	30	54	60
Other expense	89	128	181	328
Other expense-intercompany	36	96	59	187
Total operating expenses	242	366	478	794
Income (loss) before taxes and equity in undistributed income of subsidiaries	45	46	(185)	14
Provision (benefit) for income taxes	14	7	(97)	(21)
Income from continuing operations	31	39	(88)	35
Net income before attribution of noncontrolling interests	31	39	(88)	35
Citigroup's net income	31	39	(88)	35
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	31	39	(88)	35
Citigroup's other comprehensive income (loss)	(9)	44		9
Total comprehensive income before attribution of noncontrolling interests	22	83	(88)	44
Citigroup's comprehensive income	22	83	(88)	44
Associates
Condensed Consolidating Statements of Income:
Interest revenue	955	1,196	1,940	2,421
Interest revenue-intercompany	96	93	191	190
Interest expense	66	72	135	148
Interest expense-intercompany	250	320	500	644
Net interest revenue	735	897	1,496	1,819
Commissions and fees	20	20	42	43
Commissions and fees-intercompany	6	31	10	63
Principal transactions	(6)	(7)	(2)	(6)
Other income	118	118	59	257
Other income-intercompany	5	7	(22)	17
Total non-interest revenues	143	169	87	374
Total revenues, net of interest expense	878	1,066	1,583	2,193
Provisions for credit losses and for benefits and claims	427	405	933	861
Compensation and benefits	113	162	244	310
Compensation and benefits-intercompany	26	30	53	60
Other expense	120	161	249	399
Other expense-intercompany	38	104	65	204
Total operating expenses	297	457	611	973
Income (loss) before taxes and equity in undistributed income of subsidiaries	154	204	39	359
Provision (benefit) for income taxes	50	61	(20)	101
Income from continuing operations	104	143	59	258
Net income before attribution of noncontrolling interests	104	143	59	258
Citigroup's net income	104	143	59	258
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	104	143	59	258
Citigroup's other comprehensive income (loss)	(41)	115	(24)	121
Total comprehensive income before attribution of noncontrolling interests	63	258	35	379
Citigroup's comprehensive income	63	258	35	379
Other Citigroup Subsidiaries, eliminations and income from discontinued operations
Condensed Consolidating Statements of Income:
Interest revenue	14,613	15,844	29,839	31,254
Interest revenue-intercompany	(1,451)	(2,041)	(3,035)	(4,228)
Interest expense	2,647	3,022	5,363	5,866
Interest expense-intercompany	(699)	(1,095)	(1,357)	(2,237)
Net interest revenue	11,214	11,876	22,798	23,397
Commissions and fees	2,026	2,263	4,088	4,460
Commissions and fees-intercompany	(53)	(57)	(87)	(88)
Principal transactions	(447)	697	2,481	3,757
Principal transactions-intercompany	1,412	1,133	344	138
Other income	2,957	3,494	3,940	4,059
Other income-intercompany	(1,357)	(1,583)	582	(1,178)
Total non-interest revenues	4,574	5,947	11,348	11,148
Total revenues, net of interest expense	15,788	17,823	34,146	34,545
Provisions for credit losses and for benefits and claims	2,373	2,986	4,881	5,704
Compensation and benefits	4,689	4,923	9,480	9,681
Compensation and benefits-intercompany	(82)	(91)	(166)	(180)
Other expense	5,113	5,182	9,921	9,870
Other expense-intercompany	(265)	(300)	(601)	(589)
Total operating expenses	9,455	9,714	18,634	18,782
Income (loss) before taxes and equity in undistributed income of subsidiaries	3,960	5,123	10,631	10,059
Provision (benefit) for income taxes	883	1,442	2,303	2,984
Income from continuing operations	3,077	3,681	8,328	7,075
Income (loss) from discontinued operations, net of taxes	(1)	71	(6)	111
Net income before attribution of noncontrolling interests	3,076	3,752	8,322	7,186
Net income (loss) attributable to noncontrolling interests	39	43	156	104
Citigroup's net income	3,037	3,709	8,166	7,082
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	3,076	3,752	8,322	7,186
Citigroup's other comprehensive income (loss)	121	(127)	54	(157)
Other comprehensive income (loss) attributable to noncontrolling interests	(53)	24	11	53
Total comprehensive income before attribution of noncontrolling interests	3,144	3,649	8,387	7,082
Total comprehensive income (loss) attributable to noncontrolling interests	(14)	67	167	157
Citigroup's comprehensive income	3,158	3,582	8,220	6,925
Consolidating adjustments
Condensed Consolidating Statements of Income:
Dividends from subsidiaries	(3,380)	(6,645)	(4,880)	(7,170)
Interest revenue	(822)	(1,034)	(1,668)	(2,085)
Interest revenue-intercompany	(22)	(25)	(47)	(51)
Interest expense	(26)	(23)	(52)	(52)
Interest expense-intercompany	(268)	(382)	(545)	(778)
Net interest revenue	(550)	(654)	(1,118)	(1,306)
Commissions and fees	(1)	(1)	(3)	(3)
Commissions and fees-intercompany	(1)	(28)	1	(56)
Other income	(123)	(108)	(29)	(219)
Other income-intercompany	(1)	3	(1)	3
Total non-interest revenues	(126)	(134)	(32)	(275)
Total revenues, net of interest expense	(4,056)	(7,433)	(6,030)	(8,751)
Provisions for credit losses and for benefits and claims	(389)	(376)	(857)	(773)
Compensation and benefits	(90)	(112)	(184)	(219)
Compensation and benefits-intercompany	(27)	(30)	(54)	(60)
Other expense	(89)	(128)	(181)	(328)
Other expense-intercompany	(36)	(96)	(59)	(187)
Total operating expenses	(242)	(366)	(478)	(794)
Income (loss) before taxes and equity in undistributed income of subsidiaries	(3,425)	(6,691)	(4,695)	(7,184)
Provision (benefit) for income taxes	(14)	(7)	97	21
Equity in undistributed income of subsidiaries	106	2,448	(2,988)	(792)
Income from continuing operations	(3,305)	(4,196)	(7,780)	(7,997)
Net income before attribution of noncontrolling interests	(3,305)	(4,196)	(7,780)	(7,997)
Citigroup's net income	(3,305)	(4,196)	(7,780)	(7,997)
Comprehensive Income (Loss) [Abstract]
Net income before attribution of noncontrolling interests	(3,305)	(4,196)	(7,780)	(7,997)
Citigroup's other comprehensive income (loss)	9	(44)		(9)
Total comprehensive income before attribution of noncontrolling interests	(3,296)	(4,240)	(7,780)	(8,006)
Citigroup's comprehensive income	$ (3,296)	$ (4,240)	$ (7,780)	$ (8,006)