FAIR VALUE MEASUREMENT (Details 7) (USD $)	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Assets.
Investments	$ 276,489,000,000		$ 274,040,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	166,506,000,000		142,862,000,000
Loans	5,359,000,000		5,265,000,000
Other financial assets	8,426,000,000		13,360,000,000
Liabilities;
Deposits	944,644,000,000		865,936,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	123,459,000,000		97,712,000,000
Long-term debt	27,336,000,000		24,172,000,000
Other financial liabilities	3,407,000,000		3,742,000,000
Allowance for loan losses	25,916,000,000	27,611,000,000	30,115,000,000	32,052,000,000	34,362,000,000	40,655,000,000
Lease finance receivables	2,700,000,000		2,500,000,000
Consumer
Assets.
Loans	1,256,000,000		1,326,000,000
Corporate
Assets.
Loans	4,103,000,000		3,939,000,000
Nonrecurring | Loans, excluding lease finance receivables
Fair value measurements additional disclosures
Aggregate carrying value in excess of (less than) fair value	10,400,000,000		10,600,000,000
Nonrecurring | Consumer
Fair value measurements additional disclosures
Aggregate carrying value in excess of (less than) fair value	8,700,000,000
Nonrecurring | Corporate
Fair value measurements additional disclosures
Aggregate carrying value in excess of (less than) fair value	1,700,000,000
Nonrecurring | Level 1
Assets.
Investments	2,900,000,000
Other financial assets	9,500,000,000
Nonrecurring | Level 2
Assets.
Investments	14,800,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	103,300,000,000
Loans	5,000,000,000
Other financial assets	195,000,000,000
Liabilities;
Deposits	767,700,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	100,800,000,000
Long-term debt	198,900,000,000
Other financial liabilities	28,600,000,000
Nonrecurring | Level 3
Assets.
Investments	1,600,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	7,700,000,000
Loans	609,000,000,000
Other financial assets	62,000,000,000
Liabilities;
Deposits	173,600,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	100,000,000
Long-term debt	48,300,000,000
Other financial liabilities	108,000,000,000
Nonrecurring | Carrying value
Assets.
Investments	19,000,000,000		19,400,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	111,000,000,000		133,000,000,000
Loans	624,400,000,000		609,300,000,000
Other financial assets	266,500,000,000		245,700,000,000
Liabilities;
Deposits	942,800,000,000		864,600,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	100,900,000,000		100,700,000,000
Long-term debt	244,500,000,000		299,300,000,000
Other financial liabilities	136,600,000,000		141,100,000,000
Nonrecurring | Fair value
Assets.
Investments	19,300,000,000		18,400,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	111,000,000,000		133,000,000,000
Loans	614,000,000,000		598,700,000,000
Other financial assets	266,500,000,000		245,700,000,000
Liabilities;
Deposits	941,300,000,000		864,500,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	100,900,000,000		100,700,000,000
Long-term debt	247,200,000,000		289,700,000,000
Other financial liabilities	136,600,000,000		141,100,000,000
Nonrecurring | Fair value | Level 3
Fair value measurements additional disclosures
Estimated fair values of corporate unfunded lending commitments	$ 6,200,000,000		$ 4,700,000,000