BUSINESS SEGMENTS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 country	Mar. 31, 2011
Segment reporting information
Number of countries where the entity provides a broad range of banking and financial products and services	100
Revenues, net of interest expense	$ 19,406	$ 19,726
Provision for income taxes	1,006	1,185
Income (loss) from continuing operations	3,062	3,031
Pretax provisions (credits) for credit losses and for benefits and claims	3,019	3,184
Citicorp
Segment reporting information
Revenues, net of interest expense	18,032	18,138
Provision for income taxes	1,639	1,937
Income (loss) from continuing operations	4,398	4,467
Citicorp | North America
Segment reporting information
Revenues, net of interest expense	7,200	7,900
Citicorp | EMEA
Segment reporting information
Revenues, net of interest expense	3,200	3,300
Citicorp | Latin America
Segment reporting information
Revenues, net of interest expense	3,600	3,300
Citicorp | Asia
Segment reporting information
Revenues, net of interest expense	4,000	3,600
Global Consumer Banking
Segment reporting information
Revenues, net of interest expense	10,014	9,554
Provision for income taxes	1,015	865
Income (loss) from continuing operations	2,188	1,920
Pretax provisions (credits) for credit losses and for benefits and claims	1,600	1,700
Institutional Clients Group
Segment reporting information
Revenues, net of interest expense	8,018	8,584
Provision for income taxes	624	1,072
Income (loss) from continuing operations	2,210	2,547
Pretax provisions (credits) for credit losses and for benefits and claims	89	(180)
Citi Holdings
Segment reporting information
Revenues, net of interest expense	874	1,649
Provision for income taxes	(650)	(522)
Income (loss) from continuing operations	(1,024)	(957)
Pretax provisions (credits) for credit losses and for benefits and claims	1,300	1,700
Corporate/Other
Segment reporting information
Revenues, net of interest expense	500	(61)
Provision for income taxes	17	(230)
Income (loss) from continuing operations	$ (312)	$ (479)