Fair Value Measures - Roll Forward of Financial Instruments (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	$ 1,042	$ 1,032
Total Gains / (Losses) Recorded in Earnings	(12)	(60)
Purchases / Originations	68	141
Sales	(51)	(51)
Settlement	0	0
Transfers In (Out)	(16)	(31)
Balance at End of Year	1,031	1,031
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	1,034	1,033
Total Gains / (Losses) Recorded in Earnings	5	(32)
Purchases / Originations	43	81
Sales	(51)	(51)
Settlement	0
Transfers In (Out)	0	0
Balance at End of Year	1,031	1,031
Rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Year	8	(1)
Total Gains / (Losses) Recorded in Earnings	(17)	(28)
Purchases / Originations	25	60
Sales		0
Settlement		0
Transfers In (Out)	(16)	(31)
Balance at End of Year	$ 0	$ 0