INVESTMENTS (Details 8) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013		Sep. 30, 2014	Sep. 30, 2013		Jun. 30, 2014 MSSB	Sep. 30, 2014 Securities available-for-sale (AFS)		Sep. 30, 2013 Securities available-for-sale (AFS)		Sep. 30, 2014 Securities available-for-sale (AFS)		Sep. 30, 2013 Securities available-for-sale (AFS)		Sep. 30, 2013 Held-to-maturity Securities	Sep. 30, 2013 Held-to-maturity Securities	Sep. 30, 2013 Other assets
OTTI on Investments disclosures
Total OTTI losses recognized during the period	$ 11	$ 44		$ 13	$ 72			$ 11	[1]	$ 2	[1]	$ 13	[1]	$ 7	[1]	$ 42	$ 65
Less: Impairments recognized in AOCI	8	27		8	38			8	[1]			8	[1]			27	38
Net impairment losses recognized in earnings for securities that the Company does not intend to sell nor will likely be required to sell	3	17		5	34			3	[1]	2	[1]	5	[1]	7	[1]	15	27
Impairment losses recognized in earnings for securities that the Company intends to sell or more- likely-than-not will be required to sell before recovery	88	22	[2]	324	428	[2]		88	[1]	22	[1],[2]	324	[1]	236	[1],[2]			192	[2]
Net impairment losses recognized in earnings	$ 91	$ 39		$ 329	$ 462			$ 91	[1]	$ 24	[1]	$ 329	[1]	$ 243	[1]	$ 15	$ 27	$ 192	[2]
Percentage of ownership interest held							35.00%

[1] Includes OTTI on non-marketable equity securities.

[2] The impairment charge relates to the carrying value of Citi’s then-remaining 35% interest in the Morgan Stanley Smith Barney joint venture (MSSB), offset by the equity pickup from MSSB during the respective periods which was recorded in Other revenue.