PRINCIPAL TRANSACTIONS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Principal transactions revenue
Principal transactions revenue	$ 1,549		$ 1,149		$ 6,280		$ 6,337
Interest rate contracts
Principal transactions revenue
Principal transactions revenue	911	[1]	474	[1]	3,240	[1]	3,649	[1]
Foreign exchange contracts
Principal transactions revenue
Principal transactions revenue	464	[2]	579	[2]	1,637	[2]	1,737	[2]
Equity contracts
Principal transactions revenue
Principal transactions revenue	(9)	[3]	27	[3]	37	[3]	407	[3]
Commodity and other contracts
Principal transactions revenue
Principal transactions revenue	164	[4]	18	[4]	486	[4]	230	[4]
Credit derivatives
Principal transactions revenue
Principal transactions revenue	19	[5]	51	[5]	880	[5]	314	[5]
Citicorp
Principal transactions revenue
Principal transactions revenue	1,395		1,126		5,978		6,337
Global Consumer Banking
Principal transactions revenue
Principal transactions revenue	221		209		605		663
Institutional Clients Group
Principal transactions revenue
Principal transactions revenue	1,395		863		5,578		5,787
Corporate/Other
Principal transactions revenue
Principal transactions revenue	(221)		54		(205)		(113)
Citi Holdings
Principal transactions revenue
Principal transactions revenue	$ 154		$ 23		$ 302		$ 0

[1] Includes revenues from government securities and corporate debt, municipal securities, mortgage securities and other debt instruments. Also includes spot and forward trading of currencies and exchange-traded and over-the-counter (OTC) currency options, options on fixed income securities, interest rate swaps, currency swaps, swap options, caps and floors, financial futures, OTC options and forward contracts on fixed income securities.

[2] Includes revenues from foreign exchange spot, forward, option and swap contracts, as well as FX translation gains and losses.

[3] Includes revenues from common, preferred and convertible preferred stock, convertible corporate debt, equity-linked notes and exchange-traded and OTC equity options and warrants.

[4] Primarily includes revenues from crude oil, refined oil products, natural gas and other commodities trades.

[5] Includes revenues from structured credit products.