BUSINESS SEGMENTS (Details 2) (USD $) In Billions	Jun. 30, 2011	Dec. 31, 2010
Segment reporting information
Identifiable assets	$ 1,957	$ 1,914
Citicorp
Segment reporting information
Identifiable assets	1,380	1,284
Regional Consumer Banking
Segment reporting information
Identifiable assets	344	331
Institutional Clients Group
Segment reporting information
Identifiable assets	1,036	953
Citi Holdings
Segment reporting information
Identifiable assets	308	359
Corporate/Other
Segment reporting information
Identifiable assets	$ 269	$ 271