BUSINESS SEGMENTS (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Segment reporting information
Identifiable assets	$ 1,944,423	$ 1,873,878
Citicorp
Segment reporting information
Identifiable assets	1,424,000	1,365,000
Global Consumer Banking
Segment reporting information
Identifiable assets	389,000	385,000
Institutional Clients Group
Segment reporting information
Identifiable assets	1,035,000	980,000
Citi Holdings
Segment reporting information
Identifiable assets	209,000	225,000
Corporate/Other
Segment reporting information
Identifiable assets	$ 311,000	$ 284,000