BUSINESS SEGMENTS (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Segment reporting information
Identifiable assets	$ 1,881,734	$ 1,864,660
Total Citicorp and Corporate/Other
Segment reporting information
Identifiable assets	1,733,000	1,709,000
Global Consumer Banking
Segment reporting information
Identifiable assets	403,000	404,000
Institutional Clients Group
Segment reporting information
Identifiable assets	1,050,000	1,062,000
Corporate/Other
Segment reporting information
Identifiable assets	280,000	243,000
Citi Holdings
Segment reporting information
Identifiable assets	$ 149,000	$ 156,000