Goodwill, Mortgage Servicing Rights, and Other Intangible Assets - Mortgage Servicing Rights (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Mortgage servicing rights activity
Fair value at beginning of period	$ 8,522	$ 7,973	$ 5,494
MSR activity:
Originations of MSRs	325	253	798
Purchase of MSRs	601	1,028	1,400
Disposition of MSRs	(21)	(188)	(822)
Net additions/(dispositions)	905	1,093	1,376
Changes due to collection/realization of expected cash flows	(1,068)	(1,011)	(936)
Changes in valuation due to inputs and assumptions:
Changes due to market interest rates and other	670	424	2,022
Changes in valuation due to other inputs and assumptions:
Projected cash flows (e.g., cost to service)	102	(22)	14
Discount rates	14	14	0
Prepayment model changes and other	(24)	51	3
Total changes in valuation due to other inputs and assumptions	92	43	17
Total changes in valuation due to inputs and assumptions	762	467	2,039
Fair value at December 31,	9,121	8,522	7,973
Change in unrealized gains/(losses) included in income related to MSRs held at December 31,	$ 762	$ 467	$ 2,039
Contractually Specified Servicing Fee Income Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag	Contractual service fees, late fees and other ancillary fees included in income	Contractual service fees, late fees and other ancillary fees included in income	Contractual service fees, late fees and other ancillary fees included in income
Contractual service fees, late fees and other ancillary fees included in income	$ 1,606	$ 1,590	$ 1,535
Third-party mortgage loans serviced at December 31,	652,000	632,000	584,000
Servicer advances, net of an allowance for uncollectible amounts, at December 31,	$ 577	$ 659	$ 758