Mortgage Banking Activities, Managed Servicing Portfolio (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Residential mortgage servicing rights [Member]
Components of Managed Servicing Portfolio [Abstract]
Serviced and subserviced for others	$ 500,000	$ 560,000
Owned loans serviced	254,000	262,000
Total managed servicing portfolio	754,000	822,000
Total serviced for others, excluding subserviced for others	$ 499,000	$ 560,000
MSRs as a percentage of loans serviced for others	1.31%	1.33%
Weighted average note rate (mortgage loans serviced for others)	3.76%	3.76%
Servicer advances, net of an allowance for uncollectible amounts	$ 802	$ 1,103
Commercial mortgage servicing [Member]
Components of Managed Servicing Portfolio [Abstract]
Serviced and subserviced for others	539,000	548,000
Owned loans serviced	120,000	128,000
Total managed servicing portfolio	659,000	676,000
Total serviced for others, excluding subserviced for others	$ 530,000	$ 539,000
MSRs as a percentage of loans serviced for others	0.18%	0.19%
Weighted average note rate (mortgage loans serviced for others)	5.22%	5.27%
Servicer advances, net of an allowance for uncollectible amounts	$ 1,159	$ 1,031