BUSINESS SEGMENTS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Segment reporting information
Revenues, net of interest expense	$ 19,342	[1],[2]	$ 20,488	[1],[2]	$ 39,466	[1],[2]	$ 40,736	[1],[2]
Provision for income taxes	1,838		2,127		3,888		3,697
Income (loss) from continuing operations	253	[3]	4,188	[3]	4,204	[3]	8,119	[3]
Pretax provisions (credits) for credit losses and for benefits and claims	1,730.0		2,024.0		3,704.0		4,483.0
Citicorp | North America
Segment reporting information
Revenues, net of interest expense	7,900		8,200		16,400		16,900
Citicorp | EMEA
Segment reporting information
Revenues, net of interest expense	2,800		3,500		5,900		6,600
Citicorp | Latin America
Segment reporting information
Revenues, net of interest expense	3,500		3,600		6,800		7,100
Citicorp | Asia
Segment reporting information
Revenues, net of interest expense	3,600		4,000		7,300		8,000
Global Consumer Banking
Segment reporting information
Regional business	4				4
Pretax provisions (credits) for credit losses and for benefits and claims	1,500.0		1,600.0		3,100.0		3,300.0
Institutional Clients Group
Segment reporting information
Number of countries where the entity provides a broad range of banking and financial products and services	100				100
Pretax provisions (credits) for credit losses and for benefits and claims	(112.0)		(30.0)		(85.0)		35.0
Citi Holdings
Segment reporting information
Pretax provisions (credits) for credit losses and for benefits and claims	300.0		500.0		700.0		1,200.0
Operating Segments | Total Citicorp and Corporate/Other
Segment reporting information
Revenues, net of interest expense	17,879	[1]	19,392	[1]	36,547	[1]	38,735	[1]
Provision for income taxes	1,750		2,465		3,934		4,595
Income (loss) from continuing operations	3,735	[3]	4,769	[3]	7,969	[3]	9,499	[3]
Operating Segments | Global Consumer Banking
Segment reporting information
Revenues, net of interest expense	9,381	[1]	9,718	[1]	18,674	[1]	19,464	[1]
Provision for income taxes	816		968		1,574		1,890
Income (loss) from continuing operations	1,605	[3]	1,862	[3]	3,332	[3]	3,687	[3]
Operating Segments | Institutional Clients Group
Segment reporting information
Revenues, net of interest expense	8,463	[1]	9,560	[1]	17,697	[1]	19,151	[1]
Provision for income taxes	1,122		1,448		2,370		2,825
Income (loss) from continuing operations	2,562	[3]	3,136	[3]	5,527	[3]	6,206	[3]
Operating Segments | Corporate/Other
Segment reporting information
Revenues, net of interest expense	35	[1]	114	[1]	176	[1]	120	[1]
Provision for income taxes	(188)		49		(10)		(120)
Income (loss) from continuing operations	(432)	[3]	(229)	[3]	(890)	[3]	(394)	[3]
Operating Segments | Citi Holdings
Segment reporting information
Revenues, net of interest expense	1,463	[1]	1,096	[1]	2,919	[1]	2,001	[1]
Provision for income taxes	88		(338)		(46)		(898)
Income (loss) from continuing operations	$ (3,482)	[3]	$ (581)	[3]	$ (3,765)	[3]	$ (1,380)	[3]

[1] Includes Citicorp (excluding Corporate/Other) total revenues, net of interest expense, in North America of $7.9 billion and $8.2 billion; in EMEA of $2.8 billion and $3.5 billion; in Latin America of $3.5 billion and $3.6 billion; and in Asia of $3.6 billion and $4.0 billion for the three months ended June 30, 2014 and 2013, respectively. Includes Citicorp (excluding Corporate/Other) total revenues, net of interest expense, in North America of $16.4 billion and $16.9 billion; in EMEA of $5.9 billion and $6.6 billion; in Latin America of $6.8 billion and $7.1 billion; and in Asia of $7.3 billion and $8.0 billion for the six months ended June 30, 2014 and 2013, respectively. Regional numbers exclude Citi Holdings and Corporate/Other, which largely operate within the U.S.

[2] Certain prior period revenue and expense lines and totals were reclassified to conform to the current period’s presentation. See Note 3 to Notes to Consolidated Financial Statements.

[3] Includes pretax provisions (credits) for credit losses and for benefits and claims in the GCB results of $1.5 billion and $1.6 billion; in the ICG results of $(112) million and $(30) million; and in Citi Holdings results of $0.3 billion and $0.5 billion for the three months ended June 30, 2014 and 2013, respectively. Includes pretax provisions (credits) for credit losses and for benefits and claims in the GCB results of $3.1 billion and $3.3 billion; in the ICG results of $(85) million and $35.0 million; and in Citi Holdings results of $0.7 billion and $1.2 billion for the six months ended June 30, 2014 and 2013, respectively.