Mortgage Banking Activities, Mortgage Servicing Rights (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Changes in fair value:
Changes due to collection/realization of expected cash flows	$ (235)	$ (290)	$ (695)	$ (936)
Servicing Asset [Abstract]
Total MSRs	7,493	9,526	7,493	9,526	$ 8,508
Commercial mortgage servicing [Member]
Servicing Asset [Abstract]
Commercial MSRs at amortized cost, end of period	949	1,069	949	1,069
Mortgage Banking Activities Textual [Abstract]
Servicing asset at amortized cost, estimated fair value	1,400	1,900	1,400	1,900
Residential mortgage servicing rights [Member]
Changes in MSRs measured at fair value
Residential MSRs at fair value, beginning of period	7,061	8,251	7,468	9,310
Originations/purchases	22	36	61	131
Sales and other	(10)	(51)	(307)	(650)
Net additions	12	(15)	(246)	(519)
Changes in fair value:
Net changes in valuation inputs or assumptions	(294)	511	17	602
Changes due to collection/realization of expected cash flows	(235)	(290)	(695)	(936)
Total changes in fair value	(529)	221	(678)	(334)
Residential MSRs at fair value, end of period	6,544	8,457	6,544	8,457
Residential mortgage servicing rights [Member] | Market interest rates [Member]
Changes in fair value:
Net changes in valuation inputs or assumptions	(296)	562	71	699
Residential mortgage servicing rights [Member] | Servicing and foreclosure costs [Member]
Changes in fair value:
Net changes in valuation inputs or assumptions	(22)	(11)	(51)	(9)
Residential mortgage servicing rights [Member] | Discount rates [Member]
Changes in fair value:
Net changes in valuation inputs or assumptions	0	(20)	(53)	(45)
Residential mortgage servicing rights [Member] | Prepayment estimates and other [Member]
Changes in fair value:
Net changes in valuation inputs or assumptions	$ 24	$ (20)	$ 50	$ (43)