Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments Standby and Other Letters of Credit and Other Financial Guarantees (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 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	$ 1,033,610,000,000	$ 1,027,988,000,000	$ 997,503,000,000
Derivatives qualifying as guarantees
Derivative notional amount	71,268,000,000,000	69,550,000,000,000
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	640,000,000	649,000,000
Standby and Other Letters of Credit: Allowance	278,000,000	284,000,000
Guarantor Obligations, Current Carrying Value	362,000,000	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	74,534,000,000	77,081,000,000
Standby Letters of Credit and Other Financial Guarantees, Internal Credit Rating, Non Investment Grade	23,665,000,000	23,848,000,000
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	98,199,000,000	100,929,000,000
Allowance for lending-related commitments	276,000,000	282,000,000
Standby Letters of Credit, Collateral Held	41,757,000,000	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	4,181,000,000	3,998,000,000
Standby Letters of Credit and Other Financial Guarantees, Internal Credit Rating, Non Investment Grade	1,764,000,000	1,575,000,000
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	5,945,000,000	5,573,000,000
Allowance for lending-related commitments	2,000,000	2,000,000
Other Letters of Credit, Collateral Held	887,000,000	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	64,000,000	42,000,000
Derivatives qualifying as guarantees
Guarantee Obligations Maximum Exposure Derivatives	59,300,000,000	61,700,000,000
Derivative notional amount	26,600,000,000	26,500,000,000
Derivatives Maximum Exposure To Loss	2,800,000,000	2,814,000,000
Derivative Qualifying As Guarantees Payables	138,000,000	122,000,000
Derivative Qualifying As Guarantees Receivables	$ 74,000,000	$ 80,000,000