LOANS (Details 6) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Loans receivable
Loans at fair value	$ 4,988		$ 5,287
Loans, net of unearned income	646,364		655,464
Corporate
Loans receivable
Loans sold and/or reclassified to held-for-sale	1,029	925
Number of days past due for reversal of accrued interest and charging to earnings	90 days		90 days
Loans, equal to 30- 89 days past due and accruing	437		344
Loans, greater than or equal to 90 days past due and accruing	116		125
Loans, total Past due and accruing	553		469
Loans, total non-accrual	2,504		2,333
Loans, total current	244,345		239,935
Loans at fair value	3,786		4,056
Loans, net of unearned income	251,188		246,793
Number of days past due, non-accrual status	90 days		90 days
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	61		38
Loans, greater than or equal to 90 days past due and accruing	5		10
Loans, total Past due and accruing	66		48
Loans, total non-accrual	1,171		1,078
Loans, total current	111,400		107,650
Loans, net of unearned income	112,637		108,776
Corporate | Financial institutions
Loans receivable
Loans, equal to 30- 89 days past due and accruing	5		5
Loans, total Past due and accruing	5		5
Loans, total non-accrual	449		454
Loans, total current	52,885		53,858
Loans, net of unearned income	53,339		54,317
Corporate | Mortgage and real estate
Loans receivable
Loans, equal to 30- 89 days past due and accruing	234		224
Loans, greater than or equal to 90 days past due and accruing	105		109
Loans, total Past due and accruing	339		333
Loans, total non-accrual	630		680
Loans, total current	30,717		30,057
Loans, net of unearned income	31,686		31,070
Corporate | Lease financing
Loans receivable
Loans, equal to 30- 89 days past due and accruing	2		7
Loans, greater than or equal to 90 days past due and accruing	1
Loans, total Past due and accruing	3		7
Loans, total non-accrual	189		52
Loans, total current	1,770		1,956
Loans, net of unearned income	1,962		2,015
Corporate | Other
Loans receivable
Loans, equal to 30- 89 days past due and accruing	135		70
Loans, greater than or equal to 90 days past due and accruing	5		6
Loans, total Past due and accruing	140		76
Loans, total non-accrual	65		69
Loans, total current	47,573		46,414
Loans, net of unearned income	$ 47,778		$ 46,559