Standby and Other Letters of Credit and Other Financial Guarantees (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	$ 1,040,134,000,000	$ 1,027,988,000,000	$ 1,016,346,000,000
Derivatives qualifying as guarantees
Derivative notional amount	73,544,000,000,000	69,546,000,000,000
Standby and Other Letters of Credit
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Standby and Other Letters of Credit, Carrying Value	636,000,000	649,000,000
Standby and Other Letters of Credit: Allowance	290,000,000	284,000,000
Guarantor Obligations, Current Carrying Value	346,000,000	365,000,000
Standby Letters of Credit, and Other Financial Guarantees
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Standby Letters of Credit and Other Financial Guarantees, Internal Credit Rating, Investment Grade	72,107,000,000	77,081,000,000
Standby Letters of Credit and Other Financial Guarantees, Internal Credit Rating, Non Investment Grade	22,991,000,000	23,848,000,000
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	95,098,000,000	100,929,000,000
Allowance for lending-related commitments	288,000,000	282,000,000
Standby Letters of Credit, Collateral Held	41,002,000,000	42,654,000,000
Other letters of credit
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Standby Letters of Credit and Other Financial Guarantees, Internal Credit Rating, Investment Grade	4,329,000,000	3,998,000,000
Standby Letters of Credit and Other Financial Guarantees, Internal Credit Rating, Non Investment Grade	1,210,000,000	1,575,000,000
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	5,539,000,000	5,573,000,000
Allowance for lending-related commitments	2,000,000	2,000,000
Other Letters of Credit, Collateral Held	1,498,000,000	1,145,000,000
Derivatives Qualifying as Guarantees
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Guarantor Obligations, Current Carrying Value	115,000,000	42,000,000
Derivatives qualifying as guarantees
Guarantee Obligations Maximum Exposure Derivatives	56,900,000,000	61,700,000,000
Derivative notional amount	26,700,000,000	26,500,000,000
Derivatives Maximum Exposure To Loss	2,800,000,000	2,800,000,000
Derivative Qualifying As Guarantees Payables	170,000,000	122,000,000
Derivative Qualifying As Guarantees Receivables	$ 55,000,000	$ 80,000,000