Derivative And Credit-Related Financial Instruments (Narrative) (Details) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Fair value of securities pledged as collateral for derivative assets	$ 88,000,000		$ 88,000,000
Cash deposited as collateral for derivative assets	1,000,000		1,000,000
Available-for-sale securities pledged as collateral for derivative liabilities	54,000,000		54,000,000
Cash posted as collateral for derivative liabilities	44,000,000		44,000,000
Aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	17,000,000		17,000,000
Collateral pledged for aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	7,000,000		7,000,000
Additional required overnight collateral on derivatives with credit-risk contingent features at period end should the credit-risk contingent features be triggered	10,000,000		10,000,000
Net interest income generated by risk management fair value interest rate swaps	18,000,000	18,000,000	36,000,000	36,000,000
Allowance for credit losses on lending-related commitments	42,000,000		42,000,000		36,000,000
Allowance for credit losses on lending-related commitments, amount related to unused commitments to extend credit	28,000,000		28,000,000		28,000,000
Risk participation agreements covering standby and commercial letters of credit	261,000,000		261,000,000		259,000,000
Standby and commercial letters of credit	4,000,000,000		4,000,000,000		4,400,000,000
Carrying value of standby and commercial letters of credit included in accrued expenses and other liabilities	64,000,000		64,000,000		59,000,000
Deferred fees on standby and commercial letters of credit included in accrued expenses and other liabilities	50,000,000		50,000,000		51,000,000
Allowance for credit losses on lending-related commitments, amount related to standby and commercial letters of credit	14,000,000		14,000,000		8,000,000
Notional Amount of Derivative Credit Risk Participation Agreements	549,000,000		549,000,000		614,000,000
Maximum estimated exposure to credit risk participation agreements assuming 100% default	7,000,000		7,000,000		7,000,000
Weighted average remaining maturity of credit risk participation agreements, in years			2 years 9 months 10 days
Fair value of derivative liability	286,000,000		286,000,000		249,000,000
Visa derivative contract
Notional amount of the derivative contract equivalent to Visa Class B shares	780		780
Fair value of derivative liability	$ 2,000,000		$ 2,000,000		$ 2,000,000