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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	$ 1,676	$ 1,686	$ 1,685	$ 1,673
Included in earnings	(112)	24	(157)	(50)
Purchases/originations	15	24	35	80
Sales			(5)
Settlements	(4)	26	15	53
Transfers into Level 3	1	1	3	5
Balance, end of period	1,576	1,761	1,576	1,761
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	(100)	42	(120)	(20)
Derivative assets	2,098		2,098		$ 2,677
Derivative liabilities	2,427		2,427		$ 2,999
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	7	5	7	5
Derivative liabilities	5	7	5	7
Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,731	1,764	1,737	1,746
Included in earnings	(90)	34	(112)	(6)
Purchases/originations	15	24	36	82
Sales			(5)
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Balance, end of period	1,656	1,822	1,656	1,822
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	(66)	56	(44)	53
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	0	2	0	(1)
Included in earnings	18	7	38	32
Purchases/originations	0	0	(1)	(2)
Sales			0
Settlements	(16)	(11)	(35)	(31)
Transfers into Level 3	0	0	0	0
Balance, end of period	2	(2)	2	(2)
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	3	7	3
Equity Derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(164)	(204)	(168)	(195)
Included in earnings	(47)	(10)	(87)	(72)
Purchases/originations	0	0	0	0
Sales			0
Settlements	15	42	59	95
Transfers into Level 3	0	0	0	0
Balance, end of period	(196)	(172)	(196)	(172)
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	(47)	(10)	(87)	(72)
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	109	124	116	123
Included in earnings	7	(7)	4	(4)
Purchases/originations	0	0	0	0
Sales			0
Settlements	(3)	(5)	(9)	(11)
Transfers into Level 3	1	1	3	5
Balance, end of period	114	113	114	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	$ 7	$ (7)	$ 4	$ (4)