BUSINESS SEGMENTS (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Segment reporting information
Identifiable assets	$ 1,916,451	$ 1,873,878
Citicorp
Segment reporting information
Identifiable assets	1,436,000	1,365,000
Global Consumer Banking
Segment reporting information
Identifiable assets	387,000	385,000
Institutional Clients Group
Segment reporting information
Identifiable assets	1,049,000	980,000
Corporate/Other
Segment reporting information
Identifiable assets	289,000	284,000
Total Citicorp and Corporate/Other
Segment reporting information
Identifiable assets	1,725,000	1,649,000
Citi Holdings
Segment reporting information
Identifiable assets	$ 191,000	$ 225,000