LOANS - Corporate Loan Delinquency (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Loans receivable
Loans, net of unearned income	$ 632,118		$ 632,118		$ 644,635
Loans at fair value	6,538		6,538		$ 5,901
Corporate
Loans receivable
Loans sold and/or reclassified to held-for-sale	500	$ 1,400	$ 1,100	$ 2,500
Number of days past due, non-accrual status			90 days		90 days
Number of days past due for reversal of accrued interest and charging to earnings			90 days
Loans, equal to 30- 89 days past due and accruing	228		$ 228		$ 187
Loans, greater than or equal to 90 days past due and accruing	7		7		1
Loans, total Past due and accruing	235		235		188
Loans, total non-accrual	1,158		1,158		1,183
Loans, total current	281,868		281,868		267,385
Loans, net of unearned income	289,769		289,769		274,665
Loans at fair value	6,499		6,499		5,858
Purchased distressed loans	9		$ 9		$ 51
Loans less than this number of days past due are considered current			30 days		30 days
Corporate | Commercial and industrial
Loans receivable
Loans, equal to 30- 89 days past due and accruing	37		$ 37		$ 50
Loans, greater than or equal to 90 days past due and accruing	2		2		0
Loans, total Past due and accruing	39		39		50
Loans, total non-accrual	626		626		575
Loans, total current	118,357		118,357		109,764
Loans, net of unearned income	119,022		119,022		110,389
Corporate | Financial institutions
Loans receivable
Loans, equal to 30- 89 days past due and accruing	14		14		2
Loans, greater than or equal to 90 days past due and accruing	0		0		0
Loans, total Past due and accruing	14		14		2
Loans, total non-accrual	200		200		250
Loans, total current	65,750		65,750		67,580
Loans, net of unearned income	65,964		65,964		67,832
Corporate | Mortgage and real estate
Loans receivable
Loans, equal to 30- 89 days past due and accruing	123		123		86
Loans, greater than or equal to 90 days past due and accruing	0		0		0
Loans, total Past due and accruing	123		123		86
Loans, total non-accrual	247		247		252
Loans, total current	40,185		40,185		38,135
Loans, net of unearned income	40,555		40,555		38,473
Corporate | Leases
Loans receivable
Loans, equal to 30- 89 days past due and accruing	0		0		0
Loans, greater than or equal to 90 days past due and accruing	0		0		0
Loans, total Past due and accruing	0		0		0
Loans, total non-accrual	48		48		51
Loans, total current	1,968		1,968		2,062
Loans, net of unearned income	2,016		2,016		2,113
Corporate | Other
Loans receivable
Loans, equal to 30- 89 days past due and accruing	54		54		49
Loans, greater than or equal to 90 days past due and accruing	5		5		1
Loans, total Past due and accruing	59		59		50
Loans, total non-accrual	37		37		55
Loans, total current	55,608		55,608		49,844
Loans, net of unearned income	$ 55,704		$ 55,704		$ 49,949