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, 2025	Mar. 31, 2024	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	$ 1,639	$ 1,685
Included in earnings	(51)	(2)
Purchases/originations	8	11
Settlements	1	11
Transfers into Level 3	2	2
Balance, end of period	1,599	1,707
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	(45)	11
Derivative Assets	2,190		$ 2,472
Derivative Liabilities	2,485		$ 2,798
Unrealized gains or losses included in other comprehensive income for instruments still held	0	0
Interest rate contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Derivative Assets	5	6
Derivative Liabilities	5	6
Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,704	1,737
Included in earnings	(50)	8
Purchases/originations	9	11
Settlements	0	0
Transfers into Level 3	0	0
Balance, end of period	1,663	1,756
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	(35)	25
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(3)	0
Included in earnings	15	9
Purchases/originations	(1)	0
Settlements	(11)	(9)
Transfers into Level 3	0	0
Balance, end of period	0	0
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	6	5
Equity Derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(170)	(168)
Included in earnings	(18)	(17)
Purchases/originations	0	0
Settlements	15	23
Transfers into Level 3	0	0
Balance, end of period	(173)	(162)
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	(18)	(17)
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	108	116
Included in earnings	2	(2)
Purchases/originations	0	0
Settlements	(3)	(3)
Transfers into Level 3	2	2
Balance, end of period	109	113
The amount of total (losses) gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	$ 2	$ (2)