Mortgage Banking Activities, Managed Servicing Portfolio (Details) - USD ($) $ in Billions	Mar. 31, 2022	Dec. 31, 2021
Components of Managed Servicing Portfolio [Abstract]
Total managed servicing portfolio	$ 1,708.0	$ 1,721.0
Total serviced for others, excluding subserviced for others	$ 1,293.0	$ 1,304.0
MSRs as a percentage of loans serviced for others	0.75%	0.63%
Weighted average note rate (mortgage loans serviced for others)	0.0381	0.0382
Mortgage Banking Activities Textual [Abstract]
Servicer advances on mortgage loans	$ 2.9	$ 3.2
Residential mortgage servicing rights [Member]
Components of Managed Servicing Portfolio [Abstract]
Serviced and subserviced for others	705.0	718.0
Owned loans serviced	273.0	276.0
Total managed servicing portfolio	978.0	994.0
Commercial mortgage servicing [Member]
Components of Managed Servicing Portfolio [Abstract]
Serviced and subserviced for others	598.0	597.0
Owned loans serviced	132.0	130.0
Total managed servicing portfolio	$ 730.0	$ 727.0