Fair Value Measurements - Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	$ 1,686	$ 1,524	$ 1,673	$ 1,065
Included in earnings	24	19	(50)	159
Purchases/originations	24	101	80	395
Settlements	26	29	53	47
Transfers into Level 3	1	3	5	10
Balance, end of period	1,761	1,676	1,761	1,676
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	42	54	(20)	273
Derivative assets	3,303		3,303		$ 3,171
Derivative liabilities	3,772		3,772		$ 3,951
Unrealized gains or losses included in other comprehensive income for instruments still held	0	0	0	0
Interest rate contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Derivative assets	5	7	5	7
Derivative liabilities	7	14	7	14
Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,764	1,582	1,746	1,121
Included in earnings	34	48	(6)	217
Purchases/originations	24	102	82	394
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Balance, end of period	1,822	1,732	1,822	1,732
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	56	80	53	338
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	2	8	(1)	4
Included in earnings	7	(5)	32	8
Purchases/originations	0	(1)	(2)	1
Settlements	(11)	(9)	(31)	(20)
Transfers into Level 3	0	0	0	0
Balance, end of period	(2)	(7)	(2)	(7)
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	3	(2)	3	1
Equity Derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(204)	(199)	(195)	(214)
Included in earnings	(10)	(17)	(72)	(46)
Purchases/originations	0	0	0	0
Settlements	42	42	95	86
Transfers into Level 3	0	0	0	0
Balance, end of period	(172)	(174)	(172)	(174)
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	(10)	(17)	(72)	(46)
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	124	133	123	154
Included in earnings	(7)	(7)	(4)	(20)
Purchases/originations	0	0	0	0
Settlements	(5)	(4)	(11)	(19)
Transfers into Level 3	1	3	5	10
Balance, end of period	113	125	113	125
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	$ (7)	$ (7)	$ (4)	$ (20)