FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) (USD $)	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009
Assets.
Investments	$ 309,574,000,000		$ 318,164,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	283,976,000,000		246,717,000,000
Trading account assets	322,349,000,000		317,272,000,000
Allowance for loan losses	34,362,000,000	36,568,000,000	40,655,000,000	46,197,000,000	48,746,000,000	36,033,000,000
Aggregate carrying value in excess of (less than) fair value	9,700,000,000		21,200,000,000
Liabilities;
Deposits	866,310,000,000		844,968,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	203,843,000,000		189,558,000,000
Trading account liabilities	152,307,000,000		129,054,000,000
Long-term debt	352,458,000,000		381,183,000,000
Estimated fair values of corporate unfunded lending commitments	5,000,000,000		5,600,000,000
Aggregate cost
Assets.
Investments	309,600,000,000		318,200,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	284,000,000,000		246,700,000,000
Trading account assets	322,300,000,000		317,300,000,000
Loans	610,500,000,000		605,500,000,000
Other financial assets	283,800,000,000		280,500,000,000
Lease finance receivables	2,600,000,000		2,600,000,000
Liabilities;
Deposits	866,300,000,000		845,000,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	203,800,000,000		189,600,000,000
Trading account liabilities	152,300,000,000		129,100,000,000
Long-term debt	352,500,000,000		381,200,000,000
Other financial liabilities	172,900,000,000		171,200,000,000
Fair value
Assets.
Investments	309,300,000,000		319,000,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	284,000,000,000		246,700,000,000
Trading account assets	322,300,000,000		317,300,000,000
Loans	600,800,000,000		584,300,000,000
Other financial assets	283,400,000,000		280,200,000,000
Liabilities;
Deposits	864,800,000,000		843,200,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	203,800,000,000		189,600,000,000
Trading account liabilities	152,300,000,000		129,100,000,000
Long-term debt	360,000,000,000		384,500,000,000
Other financial liabilities	172,900,000,000		171,200,000,000
Consumer
Assets.
Aggregate carrying value in excess of (less than) fair value	7,800,000,000
Corporate loans:
Assets.
Aggregate carrying value in excess of (less than) fair value	$ 1,900,000,000