Loans And Leases (Schedule Of Allowance For Loan Losses) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 10,053	$ 11,957
Total allowance for loan losses	22	100	79	18
Institutional [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9,593	11,193
Total allowance for loan losses	22	31
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	460	764
Total allowance for loan losses		69
Loans And Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	477	735
Collectively evaluated for impairment	9,537	11,081
Loans acquired with deteriorated credit quality	39	141
Loans And Leases [Member] | Institutional [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	56	112
Collectively evaluated for impairment	9,537	11,081
Loans And Leases [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	421	623
Loans acquired with deteriorated credit quality	39	141
Allowance For Loan Losses [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment		24
Collectively evaluated for impairment	22	31
Loans acquired with deteriorated credit quality		45
Allowance For Loan Losses [Member] | Institutional [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment	22	31
Allowance For Loan Losses [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment		24
Loans acquired with deteriorated credit quality		$ 45