ALLOWANCE FOR CREDIT LOSSES - Allowance for Loan Losses Roll Forward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014
Allowance for credit losses
Allowance for loan losses at beginning of period	$ 14,598	$ 18,923	$ 15,994	$ 19,648
Charge-offs	(2,335)	(2,812)	(4,793)	(5,795)
Recoveries	415	623	916	1,167
Replenishment of net charge-offs	1,920	2,189	3,877	4,628
Net reserve build (releases)	(199)	(521)	(290)	(1,081)
Net specific reserve releases	(206)	(89)	(317)	(175)
Other	(118)	(423)	(1,312)	(502)
Allowance for loan losses at the end of year	14,075	17,890	14,075	17,890
Allowance for loan losses:
Determined in accordance with ASC 450-20					$ 10,714	$ 11,783
Determined in accordance with ASC 310-10-35					3,338	4,152
Allowance for loan losses	14,598	18,923	15,994	19,648	14,075	15,994
Loans, net of unearned income:
Loans collectively evaluated for impairment in accordance with ASC 450-20					608,888	617,470
Loans individually evaluated for impairment in accordance with ASC 310-10-35					16,349	20,843
Loans held at fair value					6,538	5,901
Loans, net of unearned income					632,118	644,635
Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Determined in accordance with ASC 310-30					23	59
Loans, net of unearned income:
Loans					343	421
Corporate
Allowance for credit losses
Allowance for loan losses at beginning of period	2,476	2,472	2,389	2,584
Charge-offs	(123)	(47)	(146)	(221)
Recoveries	17	36	49	65
Replenishment of net charge-offs	106	11	97	156
Net reserve build (releases)	(41)	(26)	59	(127)
Net specific reserve releases	(119)	(75)	(116)	(85)
Other	10	(1)	(6)	(2)
Allowance for loan losses at the end of year	2,326	2,370	2,326	2,370
Allowance for loan losses:
Determined in accordance with ASC 450-20					2,161	2,110
Determined in accordance with ASC 310-10-35					162	235
Allowance for loan losses	2,476	2,472	2,389	2,584	2,326	2,389
Loans, net of unearned income:
Loans collectively evaluated for impairment in accordance with ASC 450-20					281,827	267,271
Loans individually evaluated for impairment in accordance with ASC 310-10-35					1,434	1,485
Loans held at fair value					6,499	5,858
Loans, net of unearned income					289,769	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	12,122	16,451	13,605	17,064
Charge-offs	(2,212)	(2,765)	(4,647)	(5,574)
Recoveries	398	587	867	1,102
Replenishment of net charge-offs	1,814	2,178	3,780	4,472
Net reserve build (releases)	(158)	(495)	(349)	(954)
Net specific reserve releases	(87)	(14)	(201)	(90)
Other	(128)	(422)	(1,306)	(500)
Allowance for loan losses at the end of year	11,749	15,520	11,749	15,520
Allowance for loan losses:
Determined in accordance with ASC 450-20					8,553	9,673
Determined in accordance with ASC 310-10-35					3,176	3,917
Allowance for loan losses	$ 12,122	$ 16,451	$ 13,605	$ 17,064	11,749	13,605
Loans, net of unearned income:
Loans collectively evaluated for impairment in accordance with ASC 450-20					327,061	350,199
Loans individually evaluated for impairment in accordance with ASC 310-10-35					14,915	19,358
Loans held at fair value					39	43
Loans, net of unearned income					342,349	369,970
Consumer | Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Determined in accordance with ASC 310-30					20	15
Loans, net of unearned income:
Loans					$ 334	$ 370