Loans and Leases (Schedule of Allowance for Loan Losses) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	$ 147		$ 422
Loans and leases, Collectively evaluated for impairment	16,284	[1]	11,885	[1]
Total loans and leases	16,431		12,307
Institutional
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	11		11
Loans and leases, Collectively evaluated for impairment	16,255	[1]	11,885	[1]
Total loans and leases	16,266		11,896
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	136		411
Loans and leases, Collectively evaluated for impairment	29	[1]	0	[1]
Total loans and leases	$ 165		$ 411

[1] As of both June 30, 2013 and December 31, 2012, the entire $22 million allowance for loan losses was related to institutional loans collectively evaluated for impairment.