BUSINESS SEGMENTS (Details) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015 USD ($) business country market	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) business country market	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Segment reporting information
Number of markets | market		11		11
Revenues, net of interest expense	[1]	$ 19,470	$ 19,425	$ 39,206	$ 39,631
Provision for income taxes		2,036	1,921	4,156	4,052
Income (loss) from continuing operations		4,858	253	9,675	4,205
Identifiable assets		1,829,370		1,829,370		$ 1,842,181
Provisions for credit losses and for benefits and claims		1,648	1,730	3,563	3,704
Operating Segments | Citicorp
Segment reporting information
Revenues, net of interest expense		17,797	17,435	35,699	35,656
Provision for income taxes		1,877	1,844	3,843	4,116
Income (loss) from continuing operations		4,695	3,745	9,365	7,979
Identifiable assets		1,713,000		1,713,000		1,713,000
Operating Segments | Global Consumer Banking and Institutional Clients Group | North America
Segment reporting information
Revenues, net of interest expense		8,000	7,900	16,300	16,200
Operating Segments | Global Consumer Banking and Institutional Clients Group | EMEA
Segment reporting information
Revenues, net of interest expense		2,800	2,700	5,800	5,800
Operating Segments | Global Consumer Banking and Institutional Clients Group | Latin America
Segment reporting information
Revenues, net of interest expense		3,000	3,300	5,900	6,500
Operating Segments | Global Consumer Banking and Institutional Clients Group | Asia
Segment reporting information
Revenues, net of interest expense		$ 3,600	3,400	$ 7,100	6,800
Operating Segments | Global Consumer Banking
Segment reporting information
Regional business | business		4		4
Revenues, net of interest expense		$ 8,549	8,944	$ 17,211	17,788
Provision for income taxes		805	802	1,725	1,544
Income (loss) from continuing operations		1,630	1,563	3,355	3,237
Identifiable assets		395,000		395,000		406,000
Provisions for credit losses and for benefits and claims		$ 1,500	1,500	$ 3,000	3,000
Operating Segments | Institutional Clients Group
Segment reporting information
Number of countries where the entity provides a broad range of banking and financial products and services | country		100		100
Revenues, net of interest expense		$ 8,878	8,402	$ 17,906	17,556
Provision for income taxes		1,317	1,205	2,675	2,526
Income (loss) from continuing operations		2,835	2,566	5,799	5,514
Identifiable assets		1,266,000		1,266,000		1,257,000
Provisions for credit losses and for benefits and claims		(95)	(112)	(21)	(85)
Operating Segments | Corporate/Other
Segment reporting information
Revenues, net of interest expense		370	89	582	312
Provision for income taxes		(245)	(163)	(557)	46
Income (loss) from continuing operations		230	(384)	211	(772)
Identifiable assets		52,000		52,000		50,000
Operating Segments | Citi Holdings
Segment reporting information
Revenues, net of interest expense		1,673	1,990	3,507	3,975
Provision for income taxes		159	77	313	(64)
Income (loss) from continuing operations		163	(3,492)	310	(3,774)
Identifiable assets		116,000		116,000		$ 129,000
Provisions for credit losses and for benefits and claims		$ 200	$ 400	$ 600	$ 800

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