Derivative And Credit-Related Financial Instruments (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Fair value of securities pledged as collateral for derivative assets	$ 190,000,000
Fair value amount of derivative asset not offset against cash collateral	12,000,000
Available-for-sale Securities Pledged as Collateral	2,800,000,000
Aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	62,000,000
Collateral pledged for aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	47,000,000
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
Net interest income generated by risk management fair value interest rate swaps	69,000,000		72,000,000
Net gain on cutomer-initiated foreign exchange derivative contracts	1,000,000		1,000,000
Allowance for credit losses on lending-related commitments	32,000,000		26,000,000
Allowance for credit losses on lending-related commitments, unused commitments to extend credit	19,000,000		9,000,000
Latest year of contract expiration on standby and commercial letters of credit	2022
Risk participation agreements covering standby and commercial letters of credit	325,000,000		271,000,000
Standby and commercial letters of credit	5,100,000,000		5,500,000,000
Carrying value of standby and commercial letters of credit included in accrued expenses and other liabilities	82,000,000		89,000,000
Deferred fees	69,000,000		72,000,000
Allowance for credit losses on lending-related commitments, standby and commercial letters of credit	13,000,000		17,000,000
Notional Amount of Derivative Credit Risk Participation Agreements	574,000,000		394,000,000
Maximum estimated exposure to credit risk participation agreements assuming 100% default	11,000,000		12,000,000
Weighted average remaining maturity of credit risk participation agreements, in years	2 years 4 months 24 days
Notional amount of the derivative contract equivalent to Visa Class B shares	780,000
Derivative Liability, Fair Value, Gross Liability	408,000,000	[1]	403,000,000	[1]
Sterling [Member]
Allowance for credit losses on lending-related commitments	0		0
Remaining fair value adjustment for unfunded commitments and letters of credit	2,000,000		3,000,000
Derivative Financial Instruments, Liabilities [Member]
Available-for-sale Securities Pledged as Collateral	59,000,000
Risk Management Purposes [Member]
Derivative Liability, Fair Value, Gross Liability	0	[1]	1,000,000	[1]
Risk Management Purposes [Member] | 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
Indemnification Agreement [Member]
Derivative Liability, Fair Value, Gross Liability	$ 1,000,000		$ 6,000,000

[1] Asset derivatives are included in “accrued income and other assets” and liability derivatives are included in “accrued expenses and other liabilities” on the consolidated balance sheets. Included in the fair value of derivative assets and liabilities are credit valuation adjustments reflecting counterparty credit risk and credit risk of the Corporation. The fair value of derivative assets included credit valuation adjustments for counterparty credit risk totaled $4 million at December 31, 2012 and 2011.