Goodwill and Mortgage Servicing Rights - Mortgage Servicing Rights (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Mortgage Servicing Rights [Roll Forward]
Fair value at beginning of period	$ 9,167	$ 9,121
MSR activity:
Originations of MSRs	146	111
Purchase of MSRs	10	279
Disposition of MSRs	2	4
Net additions/(dispositions)	158	394
Changes due to collection/realization of expected cash flows	(270)	(261)
Changes in valuation due to inputs and assumptions:
Changes due to market interest rates and other	56	(100)
Changes in valuation due to other inputs and assumptions:
Projected cash flows (e.g., cost to service)	0	1
Discount rates	0	0
Prepayment model changes and other	(18)	(28)
Total changes in valuation due to other inputs and assumptions	(18)	(27)
Total changes in valuation due to inputs and assumptions	38	(127)
Fair value at end of period	9,093	9,127
Changes in unrealized gains/(losses) included in income related to MSRs	38	(127)
Contractual service fees, late fees and other ancillary fees included in income	410	402
Third-party mortgage loans serviced	663,000	666,000
Servicer advances, net of an allowance for uncollectible amounts	$ 458	$ 529