Loans and Leases (Schedule of Allowance for Loan Losses) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	$ 130		$ 206
Loans and leases, Collectively evaluated for impairment	15,984	[1]	13,280	[1]
Total loans and leases	16,114		13,486
Institutional
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	0		26
Loans and leases, Collectively evaluated for impairment	15,880	[1]	13,251	[1]
Total loans and leases	15,880		13,277
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, Individually evaluated for impairment	130		180
Loans and leases, Collectively evaluated for impairment	104	[1]	29	[1]
Total loans and leases	$ 234		$ 209

[1] As of March 31, 2014 and December 31, 2013, all of the allowance for loan losses of $30 million and $28 million, respectively, related to institutional loans collectively evaluated for impairment.