Derivative And Credit-Related Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Fair value of securities pledged as collateral for derivative assets	$ 206,000,000		$ 206,000,000
Fair value amount of derivative asset not offset against cash collateral	13,000,000		13,000,000
Aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	77,000,000		77,000,000
Collateral pledged for aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	62,000,000		62,000,000
Additional required overnight collateral on derivatives with credit-risk contingent features at period end should the credit-risk contingent features be triggered	15,000,000		15,000,000
Net interest income generated by risk management fair value interest rate swaps	17,000,000	18,000,000	51,000,000	54,000,000
Net gain on cutomer-initiated foreign exchange derivative contracts		1,000,000		1,000,000
Allowance for credit losses on lending-related commitments	35,000,000		35,000,000		26,000,000
Allowance for credit losses on lending-related commitments, unused commitments to extend credit	20,000,000		20,000,000		9,000,000
Latest year of contract expiration on standby and commercial letters of credit	2022		2022
Risk participation agreements covering standby and commercial letters of credit	321,000,000		321,000,000		271,000,000
Standby and commercial letters of credit	5,300,000,000		5,300,000,000		5,500,000,000
Carrying value of standby and commercial letters of credit included in accrued expenses and other liabilities	94,000,000		94,000,000		89,000,000
Deferred fees	79,000,000		79,000,000		72,000,000
Allowance for credit losses on lending-related commitments, standby and commercial letters of credit	15,000,000		15,000,000		17,000,000
Total notional amount of the credit risk participation agreements	471,000,000		471,000,000		394,000,000
Maximum estimated exposure to credit risk participation agreements assuming 100% default	13,000,000		13,000,000		12,000,000
Weighted average remaining maturity of credit risk participation agreements, in years	2 years 4 months 2 days
Notional amount of the derivative contract equivalent to Visa Class B shares	780,000		780,000
Fair value of Visa Class B derivative contract					6,000,000
Sterling [Member]
Allowance for credit losses on lending-related commitments	0		0		0
Remaining fair value adjustment for unfunded commitments and letters of credit	2,000,000		2,000,000		3,000,000
Fair Value Hedging [Member]
Net gain recognized for the ineffective portion of risk management fair value interest rate swaps	(1,000,000)		(1,000,000)	1,000,000
Derivative Financial Instruments, Liabilities [Member]
Available-for-sale Securities Pledged as Collateral	$ 78,000,000		$ 78,000,000