FAIR VALUE MEASUREMENT (Details 5) (USD $) In Millions, unless otherwise specified			3 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Morgan Stanley Smith Barney joint venture	Sep. 16, 2012 Morgan Stanley Smith Barney joint venture	Sep. 30, 2012 Nonrecurring Nonrecurring fair value changes included in earnings	Sep. 30, 2011 Nonrecurring Nonrecurring fair value changes included in earnings	Sep. 30, 2012 Nonrecurring Nonrecurring fair value changes included in earnings	Sep. 30, 2011 Nonrecurring Nonrecurring fair value changes included in earnings	Sep. 30, 2012 Nonrecurring Nonrecurring fair value changes included in earnings Morgan Stanley Smith Barney joint venture	Sep. 30, 2012 Nonrecurring Fair value	Dec. 31, 2011 Nonrecurring Fair value	Sep. 30, 2012 Nonrecurring Fair value Morgan Stanley Smith Barney joint venture	Sep. 30, 2012 Nonrecurring Level 2	Dec. 31, 2011 Nonrecurring Level 2	Sep. 30, 2012 Nonrecurring Level 3	Dec. 31, 2011 Nonrecurring Level 3
Items Measured at Fair Value on a Nonrecurring Basis
Loans held-for-sale										$ 1,853	$ 2,644		$ 637	$ 1,668	$ 1,216	$ 976
Other real estate owned										207	271		44	88	163	183
Loans	5,359	5,265								5,296	3,911		4,830	3,185	466	726
Other assets	8,426	13,360								4,725			4,725
Total assets										12,081	6,826		10,236	4,941	1,845	1,885
Nonrecurring fair value changes included in earnings
Loans held-for-sale					(12)	(114)	(11)	(215)
Other real estate owned					(7)	(56)	(22)	(74)
Loans					(957)	(376)	(1,461)	(855)
Other assets					(3,340)		(3,340)
Total nonrecurring fair value gains (losses)					(4,316)	(546)	(4,834)	(1,144)
Percentage of ownership interest held			35.00%	49.00%								35.00%
Impairment charge related to investment			$ 3,340						$ 3,340