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
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation
Derivative assets	$ 4,262		$ 2,896
Derivative liabilities	4,239		$ 2,013
Unrealized gains or losses included in other comprehensive income for instruments still held	0	$ 0
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,065	669
Total (losses) gains (realized/unrealized) included in earnings	122	92
Purchases/originations	184	56
Settlements	12	(54)
Transfers into Level 3	6	9
Balance, end of period	1,389	772
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	197	153
Interest rate contracts | Level 3
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation
Derivative assets	8	39
Derivative liabilities	10	9
Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,121	656
Total (losses) gains (realized/unrealized) included in earnings	137	71
Purchases/originations	186	57
Settlements	0	0
Transfers into Level 3	0	0
Balance, end of period	1,444	784
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	207	138
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	4	53
Total (losses) gains (realized/unrealized) included in earnings	2	35
Purchases/originations	(2)	(1)
Settlements	(6)	(57)
Transfers into Level 3	0	0
Balance, end of period	(2)	30
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	29
Equity Derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(214)	(201)
Total (losses) gains (realized/unrealized) included in earnings	(11)	(13)
Purchases/originations	0	0
Settlements	27	19
Transfers into Level 3	0	0
Balance, end of period	(198)	(195)
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	(11)	(13)
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	154	161
Total (losses) gains (realized/unrealized) included in earnings	(6)	(1)
Purchases/originations	0	0
Settlements	(9)	(16)
Transfers into Level 3	6	9
Balance, end of period	145	153
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	$ (6)	$ (1)