LOANS (Details 6) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012 D	Mar. 31, 2011	Dec. 31, 2011 D
Loans receivable
Loans	$ 4,744	$ 4,351	$ 5,265
Loans, net of unearned income	648,022		647,242
Corporate
Loans receivable
Held-for-investment corporate loans sold and/or reclassified	925	2,145
Number of days past due for reversal of accrued interest and charging to earnings (in days)	90		90
Loans, equal to 30- 89 days past due and accruing	374		545
Loans, greater than or equal to 90 days past due and accruing	143		183
Loans, total Past due and accruing	517		728
Loans, total non-accrual	2,973		3,236
Recorded investment in loans	224,999		215,999
Loans	3,430		3,939
Loans, net of unearned income	231,919		223,902
Number of days past due, non-accrual status	90		90
Loans less than this number of days past due are considered current	30		30
Corporate | Commercial and industrial
Loans receivable
Loans, equal to 30- 89 days past due and accruing	60		93
Loans, greater than or equal to 90 days past due and accruing	9		30
Loans, total Past due and accruing	69		123
Loans, total non-accrual	1,228		1,144
Recorded investment in loans	104,122		98,968
Loans, net of unearned income	105,419		100,235
Corporate | Loans to financial institutions
Loans receivable
Loans, greater than or equal to 90 days past due and accruing			2
Loans, total Past due and accruing			2
Loans, total non-accrual	615		779
Recorded investment in loans	66,286		60,762
Loans, net of unearned income	66,901		61,543
Corporate | Mortgage and real estate
Loans receivable
Loans, equal to 30- 89 days past due and accruing	202		224
Loans, greater than or equal to 90 days past due and accruing	128		125
Loans, total Past due and accruing	330		349
Loans, total non-accrual	942		1,029
Recorded investment in loans	27,843		26,107
Loans, net of unearned income	29,115		27,485
Corporate | Lease financing
Loans receivable
Loans, equal to 30- 89 days past due and accruing	2		3
Loans, greater than or equal to 90 days past due and accruing			11
Loans, total Past due and accruing	2		14
Loans, total non-accrual	11		13
Recorded investment in loans	1,831		1,811
Loans, net of unearned income	1,844		1,838
Corporate | Other
Loans receivable
Loans, equal to 30- 89 days past due and accruing	110		225
Loans, greater than or equal to 90 days past due and accruing	6		15
Loans, total Past due and accruing	116		240
Loans, total non-accrual	177		271
Recorded investment in loans	24,917		28,351
Loans, net of unearned income	$ 25,210		$ 28,862