Fair Value Measurement - Roll Forward of Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Noninterest Income	Noninterest Income
Significant Unobservable Inputs (Level 3)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	$ 1,152	$ 1,032
Total Gains / (Losses) Recorded in Earnings	(69)	(128)
Purchases / Originations	241	312
Sales	(1,194)	(51)
Transfers In (Out)	(71)	(13)
Balance at End of Year	59	1,152
Significant Unobservable Inputs (Level 3) | Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	1,111	1,033
Total Gains / (Losses) Recorded in Earnings	(75)	(79)
Purchases / Originations	184	208
Sales	(1,194)	(51)
Transfers In (Out)	0	0
Balance at End of Year	26	1,111
Significant Unobservable Inputs (Level 3) | Private label collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	32	0
Total Gains / (Losses) Recorded in Earnings	1	0
Purchases / Originations	0	0
Sales	0	0
Transfers In (Out)	0	32
Balance at End of Year	33	32
Significant Unobservable Inputs (Level 3) | Rate lock commitments (net)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	9	(1)
Total Gains / (Losses) Recorded in Earnings	5	(49)
Purchases / Originations	57	104
Sales	0	0
Transfers In (Out)	(71)	(45)
Balance at End of Year	$ 0	$ 9