Mortgage Banking Activities, Managed Servicing Portfolio Components (Details) - USD ($) $ in Billions	Jun. 30, 2015	Dec. 31, 2014
Components of Managed Servicing Portfolio [Abstract]
Serviced for others	$ 1,809	$ 1,861
Total managed servicing portfolio	$ 2,288	$ 2,327
Ratio of MSRs to related loans serviced for others	0.77%	0.75%
Residential Mortgage Servicing [Member]
Components of Managed Servicing Portfolio [Abstract]
Serviced for others	$ 1,344	$ 1,405
Owned loans serviced	347	342
Subserviced for others	5	5
Total managed servicing portfolio	1,696	1,752
Commercial Mortgage Servicing [Member]
Components of Managed Servicing Portfolio [Abstract]
Serviced for others	465	456
Owned loans serviced	120	112
Subserviced for others	7	7
Total managed servicing portfolio	$ 592	$ 575