Goodwill, Mortgage Servicing Rights, and Other Intangible Assets - Mortgage Servicing Rights (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Mortgage Servicing Rights [Roll Forward]
Fair value at beginning of period	$ 8,996	$ 8,847	$ 9,121	$ 8,522
MSR activity:
Originations of MSRs	102	75	297	228
Purchase of MSRs	246	282	526	607
Disposition of MSRs	1	2	8	(25)
Net additions/(dispositions)	349	359	831	810
Changes due to collection/realization of expected cash flows	(266)	(272)	(799)	(795)
Changes in valuation due to inputs and assumptions:
Changes due to market interest rates and other	(3)	(251)	(44)	134
Changes in valuation due to other inputs and assumptions:
Projected cash flows (e.g., cost to service)	(37)	95	(36)	102
Discount rates	0	14	(1)	14
Prepayment model changes and other	71	(39)	38	(34)
Total changes in valuation due to other inputs and assumptions	34	70	1	82
Total changes in valuation due to inputs and assumptions	31	(181)	(43)	216
Fair value at end of period	9,110	8,753	9,110	8,753
Changes in unrealized gains/(losses) included in income related to MSRs	31	(181)	(43)	216
Contractual service fees, late fees and other ancillary fees included in income	404	396	1,218	1,190
Third-party mortgage loans serviced	669,000	658,000	669,000	658,000
Servicer advances, net of an allowance for uncollectible amounts	$ 415	$ 501	$ 415	$ 501