Loans and Leases - Recorded Investment in Each Class of Total Loans and Leases by Credit Quality Indicator (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 18,590	$ 18,199
Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	13,812	13,721
Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	3,692	3,317
Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	109	130
Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	942	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	15,454	15,421
Investment grade | Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	13,353	13,304
Investment grade | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	1,049	1,011
Investment grade | Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	109	130
Investment grade | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	915	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	3,090	2,778
Speculative | Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	438	417
Speculative | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	2,618	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
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	46
Special Mention | Investment Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	21
Special Mention | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	25
Special Mention | Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	0
Special Mention | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	0
Special Mention | Property Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	0
Special Mention | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 0