Loan Sale and Servicing Activities and Variable Interest Entities (Narrative) (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Loan Sale and Servicing Activities and Variable Interest Entities [Abstract]
Balance Of Removal Of Account Provision Asset And Liability	$ 149,000,000	$ 190,000,000
Liquidity Facilities Fund Obligations	11,400,000,000
Percentage Of Program Level Credit Enhancement To Cover Net Losses	10.00%
Date Facility Expires	June 2018
Amount Outstanding On Facility	1,200,000,000
Deconsolidation Of Vie Net Assets	$ 675,000,000