GOODWILL AND INTANGIBLE ASSETS (Details 2) (USD $) In Millions, unless otherwise specified	0 Months Ended	12 Months Ended
	Jul. 02, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill
Balance of goodwill at beginning of period		$ 25,673	$ 25,413
Goodwill disposed of during the period		(82)	(8)
Other		(582)	268
Balance of goodwill at end of period		25,009	25,673	25,413
Goodwill written off due to impairment	0	0	0	0
Goodwill		25,009	25,673	25,413
Global Consumer Banking
Goodwill
Balance of goodwill at beginning of period		14,539	10,236
Goodwill disposed of during the period		(82)
Other		(472)	20
Intersegment transfers in/(out)			4,283
Balance of goodwill at end of period		13,985	14,539
Goodwill		13,985	14,539
North America Regional Consumer Banking
Goodwill
Balance of goodwill at end of period		6,785
Fair value as a percentage of allocated book value		183.00%
Goodwill		6,785
EMEA Regional Consumer Banking
Goodwill
Balance of goodwill at end of period		355
Fair value as a percentage of allocated book value		159.00%
Goodwill		355
Asia Regional Consumer Banking
Goodwill
Balance of goodwill at end of period		5,067
Fair value as a percentage of allocated book value		251.00%
Goodwill		5,067
LATAM America Regional Consumer Banking
Goodwill
Balance of goodwill at end of period		1,778
Fair value as a percentage of allocated book value		244.00%
Goodwill		1,778
Institutional Clients Group
Goodwill
Balance of goodwill at beginning of period		10,981	10,737
Other		(113)	244
Balance of goodwill at end of period		10,868	10,981
Goodwill		10,868	10,981
Securities and Banking
Goodwill
Balance of goodwill at end of period		9,270
Fair value as a percentage of allocated book value		147.00%
Goodwill		9,270
Transaction Services
Goodwill
Balance of goodwill at end of period		1,598
Fair value as a percentage of allocated book value		717.00%
Goodwill		1,598
Latin America Retirement Services
Goodwill
Balance of goodwill at end of period		42
Fair value as a percentage of allocated book value		224.00%
Goodwill		42
Citi Holdings
Goodwill
Balance of goodwill at beginning of period		153	4,440
Goodwill disposed of during the period			(8)
Other		3	4
Intersegment transfers in/(out)			(4,283)
Balance of goodwill at end of period		156	153
Fair value as a percentage of allocated book value		170.00%
Goodwill		$ 156	$ 153