ALLOWANCE FOR CREDIT LOSSES - Allowance for Loan Losses Roll Forward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Allowance for credit losses
Allowance for loan losses at beginning of period	$ 14,075	$ 17,890	$ 15,994	$ 19,648
Charge-offs	(2,068)	(2,586)	(6,861)	(8,381)
Recoveries	405	489	1,321	1,656
Replenishment of net charge-offs	1,663	2,097	5,540	6,725
Net reserve builds (releases)	43	(492)	(247)	(1,573)
Net specific reserve releases	(124)	(30)	(441)	(205)
Other	(368)	(453)	(1,680)	(955)
Allowance for loan losses at the end of year	13,626	16,915	13,626	16,915
Allowance for loan losses:
Determined in accordance with ASC 450					$ 10,553	$ 11,783
Determined in accordance with ASC 310-10-35					3,052	4,152
Allowance for loan losses	14,075	17,890	15,994	19,648	13,626	15,994
Loans, net of unearned income:
Loans collectively evaluated for impairment in accordance with ASC 450-20					601,163	617,470
Loans individually evaluated for impairment in accordance with ASC 310-10-35					15,448	20,843
Loans held at fair value					5,513	5,901
Loans, net of unearned income					622,444	644,635
Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Determined in accordance with ASC 310-30					21	59
Loans, net of unearned income:
Loans					320	421
Corporate
Allowance for credit losses
Allowance for loan losses at beginning of period	2,326	2,370	2,389	2,584
Charge-offs	(73)	(43)	(219)	(264)
Recoveries	27	61	76	126
Replenishment of net charge-offs	46	(18)	143	138
Net reserve builds (releases)	115	(99)	174	(226)
Net specific reserve releases	78	87	(38)	2
Other	(3)	(18)	(9)	(20)
Allowance for loan losses at the end of year	2,516	2,340	2,516	2,340
Allowance for loan losses:
Determined in accordance with ASC 450					2,271	2,110
Determined in accordance with ASC 310-10-35					242	235
Allowance for loan losses	2,326	2,370	2,389	2,584	2,516	2,389
Loans, net of unearned income:
Loans collectively evaluated for impairment in accordance with ASC 450-20					281,785	267,271
Loans individually evaluated for impairment in accordance with ASC 310-10-35					1,801	1,485
Loans held at fair value					5,476	5,858
Loans, net of unearned income					289,071	274,665
Corporate | Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Determined in accordance with ASC 310-30					3	44
Loans, net of unearned income:
Loans					9	51
Consumer
Allowance for credit losses
Allowance for loan losses at beginning of period	11,749	15,520	13,605	17,064
Charge-offs	(1,995)	(2,543)	(6,642)	(8,117)
Recoveries	378	428	1,245	1,530
Replenishment of net charge-offs	1,617	2,115	5,397	6,587
Net reserve builds (releases)	(72)	(393)	(421)	(1,347)
Net specific reserve releases	(202)	(117)	(403)	(207)
Other	(365)	(435)	(1,671)	(935)
Allowance for loan losses at the end of year	11,110	14,575	11,110	14,575
Allowance for loan losses:
Determined in accordance with ASC 450					8,282	9,673
Determined in accordance with ASC 310-10-35					2,810	3,917
Allowance for loan losses	$ 11,749	$ 15,520	$ 13,605	$ 17,064	11,110	13,605
Loans, net of unearned income:
Loans collectively evaluated for impairment in accordance with ASC 450-20					319,378	350,199
Loans individually evaluated for impairment in accordance with ASC 310-10-35					13,647	19,358
Loans held at fair value					37	43
Loans, net of unearned income					333,373	369,970
Consumer | Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Determined in accordance with ASC 310-30					18	15
Loans, net of unearned income:
Loans					$ 311	$ 370