Loans and Leases (Schedule Of Allowance For Loan Losses) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	$ 422		$ 477
Loans and leases, Collectively evaluated for impairment	11,885	[1]	9,537	[1]
Loans and leases, Loans acquired with deteriorated credit quality	0		39
Total loans and leases	12,307		10,053
Institutional [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	11		56
Loans and leases, Collectively evaluated for impairment	11,885	[1]	9,537	[1]
Loans and leases, Loans acquired with deteriorated credit quality	0		0
Total loans and leases	11,896		9,593
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	411		421
Loans and leases, Collectively evaluated for impairment	0	[1]	0	[1]
Loans and leases, Loans acquired with deteriorated credit quality	0		39
Total loans and leases	$ 411		$ 460

[1] As of both December 31, 2012 and 2011, the entire $22 million allowance for loan losses was related to institutional loans collectively evaluated for impairment.