Servicing Activities (Schedule Of Unpaid Principal Balance Of Serviced Mortgage Assets) (Details) (Residential Mortgage [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Serviced Mortgage Assets [Line Items]
Total Primary Serviced Assets	$ 8,374	$ 130,324
On-Balance Sheet Loans [Member] | Held for Sale and Investment [Member]
Serviced Mortgage Assets [Line Items]
Total Primary Serviced Assets	8,243	10,938
Off-Balance Sheet Loans [Member] | US Government-sponsored Enterprises [Member]
Serviced Mortgage Assets [Line Items]
Total Primary Serviced Assets	131	119,384
Off-Balance Sheet Loans [Member] | Whole-Loan Transactions [Member]
Serviced Mortgage Assets [Line Items]
Total Primary Serviced Assets	$ 0	$ 2