Goodwill, Mortgage Servicing Rights, and Other Intangible Assets - 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
Mortgage Servicing Rights [Roll Forward]
Fair value at beginning of period	$ 8,847	$ 8,229	$ 8,522	$ 7,973
MSR activity:
Originations of MSRs	75	81	228	191
Purchase of MSRs	282	569	607	1,036
Disposition of MSRs	2	(101)	(25)	(191)
Net additions/(dispositions)	359	549	810	1,036
Changes due to collection/realization of expected cash flows	(272)	(265)	(795)	(760)
Changes in valuation due to inputs and assumptions:
Changes due to market interest rates and other	(251)	555	134	816
Changes in valuation due to other inputs and assumptions:
Projected cash flows (e.g., cost to service)	95	(26)	102	(24)
Discount rates	14	14	14	14
Prepayment model changes and other	(39)	53	(34)	54
Total changes in valuation due to other inputs and assumptions	70	41	82	44
Total changes in valuation due to inputs and assumptions	(181)	596	216	860
Fair value at end of period	8,753	9,109	8,753	9,109
Changes in unrealized gains/(losses) included in income related to MSRs	(181)	596	216	860
Contractual service fees, late fees and other ancillary fees included in income	396	409	1,190	1,185
Third-party mortgage loans serviced	658,000	639,000	658,000	639,000
Servicer advances, net of an allowance for uncollectible amounts	$ 501	$ 557	$ 501	$ 557