Loans Held for Sale - Loans Held for Sale (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	$ 969	$ 230
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	864	76
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	105	154
Consumer Loans [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	42	91
Consumer Loans [Member] | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	$ 63	$ 63