FAIR VALUE MEASUREMENT (Details 6) (USD $)	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Assets.
Investments	$ 286,333,000,000		$ 274,040,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	167,973,000,000		142,862,000,000
Loans	5,089,000,000		5,265,000,000
Other financial assets	11,867,000,000		13,360,000,000
Liabilities;
Deposits	914,308,000,000		865,936,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	132,637,000,000		112,770,000,000
Long-term debt	26,517,000,000		24,172,000,000
Other financial liabilities	3,790,000,000		3,742,000,000
Allowance for loan losses	27,611,000,000	29,020,000,000	30,115,000,000	34,362,000,000	36,568,000,000	40,655,000,000
Lease finance receivables	2,600,000,000		2,500,000,000
Consumer
Assets.
Loans	1,260,000,000		1,326,000,000
Corporate
Assets.
Loans	3,829,000,000		3,939,000,000
Carrying value
Assets.
Investments	19,600,000,000		19,400,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	104,700,000,000		133,000,000,000
Loans	619,700,000,000		609,300,000,000
Other financial assets	255,900,000,000		245,700,000,000
Liabilities;
Deposits	912,900,000,000		864,600,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	82,200,000,000		85,600,000,000
Long-term debt	261,800,000,000		299,300,000,000
Other financial liabilities	148,800,000,000		141,100,000,000
Fair value
Assets.
Investments	19,400,000,000		18,400,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	104,700,000,000		133,000,000,000
Loans	608,500,000,000		598,700,000,000
Other financial assets	255,900,000,000		245,700,000,000
Liabilities;
Deposits	911,100,000,000		864,500,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	82,200,000,000		85,600,000,000
Long-term debt	259,400,000,000		289,700,000,000
Other financial liabilities	148,800,000,000		141,100,000,000
Fair value measurements additional disclosures
Estimated fair values of corporate unfunded lending commitments	6,400,000,000		4,700,000,000
Financial instruments not carried at Fair Value | Loans, excluding lease finance receivables
Fair value measurements additional disclosures
Aggregate carrying value in excess of (less than) fair value	11,200,000,000		10,600,000,000
Financial instruments not carried at Fair Value | Consumer
Fair value measurements additional disclosures
Aggregate carrying value in excess of (less than) fair value	8,300,000,000
Financial instruments not carried at Fair Value | Corporate
Fair value measurements additional disclosures
Aggregate carrying value in excess of (less than) fair value	2,900,000,000
Financial instruments not carried at Fair Value | Level 1
Assets.
Investments	2,700,000,000
Other financial assets	9,700,000,000
Financial instruments not carried at Fair Value | Level 2
Assets.
Investments	15,300,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	95,000,000,000
Loans	4,500,000,000
Other financial assets	179,800,000,000
Liabilities;
Deposits	723,800,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	81,000,000,000
Long-term debt	208,800,000,000
Other financial liabilities	28,900,000,000
Financial instruments not carried at Fair Value | Level 3
Assets.
Investments	1,400,000,000
Federal funds sold and securities borrowed or purchased under agreements to resell	9,700,000,000
Loans	604,000,000,000
Other financial assets	66,400,000,000
Liabilities;
Deposits	187,300,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	1,200,000,000
Long-term debt	50,600,000,000
Other financial liabilities	$ 119,900,000,000