Loans and Leases - Recorded Investment in Each Class of Total Loans and Leases by Credit Quality Indicator (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 18,319	$ 18,199
Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	13,460	13,721
Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	3,762	3,317
Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	119	130
Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	943	1,003
Property Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	7	0
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	28	28
Investment grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	15,546	15,421
Investment grade | Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	13,351	13,304
Investment grade | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	1,132	1,011
Investment grade | Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	119	130
Investment grade | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	916	976
Investment grade | Property Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	0	0
Investment grade | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	28	0
Speculative
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	2,773	2,778
Speculative | Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	109	417
Speculative | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	2,630	2,306
Speculative | Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	0	0
Speculative | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	27	27
Speculative | Property Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	7	0
Speculative | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 0	$ 28