PRINCIPAL TRANSACTIONS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Principal transactions revenue
Principal transactions revenue	$ 1,931	$ 3,167
Interest rate contracts
Principal transactions revenue
Principal transactions revenue	791	1,624
Foreign exchange contracts
Principal transactions revenue
Principal transactions revenue	754	787
Equity contracts
Principal transactions revenue
Principal transactions revenue	342	428
Commodity and other contracts
Principal transactions revenue
Principal transactions revenue	(21)	(25)
Credit derivatives
Principal transactions revenue
Principal transactions revenue	65	353
Citicorp
Principal transactions revenue
Principal transactions revenue	2,172	2,353
Global Consumer Banking
Principal transactions revenue
Principal transactions revenue	256	93
Institutional Clients Group
Principal transactions revenue
Principal transactions revenue	1,916	2,260
Citi Holdings
Principal transactions revenue
Principal transactions revenue	(121)	627
Local Consumer Lending
Principal transactions revenue
Principal transactions revenue	(23)	(17)
Brokerage and Asset Management
Principal transactions revenue
Principal transactions revenue	5	12
Special Asset Pool
Principal transactions revenue
Principal transactions revenue	(103)	632
Corporate/Other
Principal transactions revenue
Principal transactions revenue	$ (120)	$ 187