Trading Assets and Liabilities and Derivatives - Additional Information (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount of Repurchase Agreements Secured by Trading Assets	$ 717	$ 703
Repurchase Agreements [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities Pledged as Collateral	731	727
Derivative [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities Pledged as Collateral	$ 97	$ 86