Loans Held for Sale - Additional Information (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	$ 969	$ 230
Fair value of commercial syndicated loans held for sale	753	58
Fair value of commercial real estate loans held for sale	57	18
Residential mortgage loans held for sale include subprime residential mortgage loans at fair value	27	46
Valuation allowance on loans held for sale	574	606	568	647
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	864	76
Fair value of commercial syndicated loans held for sale	753	58
Commercial Loans - Global Banking [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	54
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	105	154
Valuation allowance on loans held for sale	$ 59	$ 77