BUSINESS SEGMENTS (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) business country	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment reporting information
Revenues, net of interest expense	$ 17,555	$ 19,736
Provision for income taxes	1,479	2,120
Income (loss) from continuing operations	3,508	4,817
Identifiable assets	1,800,967		$ 1,731,210
Provisions for credit losses and for benefits and claims	2,045	1,915
Operating Segments | Total Citicorp and Corporate/Other
Segment reporting information
Revenues, net of interest expense	16,080	17,591
Provision for income taxes	1,349	1,971
Income (loss) from continuing operations	3,161	4,667
Identifiable assets	1,728,000		1,650,000
Operating Segments | Citicorp | North America
Segment reporting information
Revenues, net of interest expense	7,900	8,500
Operating Segments | Citicorp | EMEA
Segment reporting information
Revenues, net of interest expense	2,200	2,900
Operating Segments | Citicorp | Latin America
Segment reporting information
Revenues, net of interest expense	2,200	2,400
Operating Segments | Citicorp | Asia
Segment reporting information
Revenues, net of interest expense	$ 3,500	3,600
Operating Segments | Global Consumer Banking
Segment reporting information
Number of regional business | business	4
Revenues, net of interest expense	$ 7,770	8,302
Provision for income taxes	646	917
Income (loss) from continuing operations	1,231	1,712
Identifiable assets	385,000		381,000
Provisions for credit losses and for benefits and claims	1,500	1,400
Operating Segments | Institutional Clients Group
Segment reporting information
Revenues, net of interest expense	8,036	9,077
Provision for income taxes	818	1,365
Income (loss) from continuing operations	1,959	2,974
Identifiable assets	1,292,000		1,217,000
Provisions for credit losses and for benefits and claims	390	86
Operating Segments | Corporate/Other
Segment reporting information
Revenues, net of interest expense	274	212
Provision for income taxes	(115)	(311)
Income (loss) from continuing operations	(29)	(19)
Identifiable assets	51,000		52,000
Operating Segments | Citi Holdings
Segment reporting information
Revenues, net of interest expense	1,475	2,145
Provision for income taxes	130	149
Income (loss) from continuing operations	347	150
Identifiable assets	73,000		$ 81,000
Provisions for credit losses and for benefits and claims	$ 200	$ 500
Minimum | 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	95