Fair Value Measurements - Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	$ 1,685	$ 1,673	$ 1,065
Included in earnings	(175)	(144)	97
Purchases/originations	48	93	449
Sales	(5)
Settlements	82	57	52
Transfers into Level 3	4	6	10
Balance, end of period	1,639	1,685	1,673
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to instruments still held	(119)	(115)	215
Derivative assets	2,472	2,677
Derivative liabilities	2,798	2,999
Unrealized gains or losses included in other comprehensive income for instruments still held	0	0	0
Interest Rate Contract | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Derivative assets	2	6	7
Derivative liabilities	5	6	8
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	116	123	154
Included in earnings	(1)	2	(18)
Purchases/originations	0	0	0
Sales	0
Settlements	(11)	(15)	(23)
Transfers into Level 3	4	6	10
Balance, end of period	108	116	123
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to instruments still held	(1)	2	(18)
Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,737	1,746	1,121
Included in earnings	(77)	(105)	177
Purchases/originations	49	96	448
Sales	(5)
Settlements	0	0	0
Transfers into Level 3	0	0	0
Balance, end of period	1,704	1,737	1,746
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to instruments still held	14	(28)	311
Interest Rate Contract
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	0	(1)	4
Included in earnings	41	53	22
Purchases/originations	(1)	(3)	1
Sales	0
Settlements	(43)	(49)	(28)
Transfers into Level 3	0	0	0
Balance, end of period	(3)	0	(1)
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to instruments still held	6	5	6
Equity Derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(168)	(195)	(214)
Included in earnings	(138)	(94)	(84)
Purchases/originations	0	0	0
Sales	0
Settlements	136	121	103
Transfers into Level 3	0	0	0
Balance, end of period	(170)	(168)	(195)
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to instruments still held	$ (138)	$ (94)	$ (84)