Fair Value Measurements - Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	$ 1,673,000,000	$ 1,065,000,000	$ 669,000,000
Included in earnings	(144,000,000)	97,000,000	(74,000,000)
Purchases/originations	93,000,000	449,000,000	601,000,000
Settlements	57,000,000	52,000,000	(180,000,000)
Transfers into Level 3	6,000,000	10,000,000	49,000,000
Balance, end of period	1,685,000,000	1,673,000,000	1,065,000,000
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	(115,000,000)	215,000,000	5,000,000
Derivative assets	2,677,000,000	3,173,000,000
Derivative liabilities	2,999,000,000	3,952,000,000
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	6,000,000	7,000,000	12,000,000
Derivative liabilities	6,000,000	8,000,000	8,000,000
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	123,000,000	154,000,000	161,000,000
Included in earnings	2,000,000	(18,000,000)	(2,000,000)
Purchases/originations	0	0	0
Settlements	(15,000,000)	(23,000,000)	(54,000,000)
Transfers into Level 3	6,000,000	10,000,000	49,000,000
Balance, end of period	116,000,000	123,000,000	154,000,000
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	2,000,000	(18,000,000)	(2,000,000)
Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	1,746,000,000	1,121,000,000	656,000,000
Included in earnings	(105,000,000)	177,000,000	(139,000,000)
Purchases/originations	96,000,000	448,000,000	604,000,000
Settlements	0	0	0
Transfers into Level 3	0	0	0
Balance, end of period	1,737,000,000	1,746,000,000	1,121,000,000
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	(28,000,000)	311,000,000	78,000,000
Interest Rate Contract
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(1,000,000)	4,000,000	53,000,000
Included in earnings	53,000,000	22,000,000	153,000,000
Purchases/originations	(3,000,000)	1,000,000	(3,000,000)
Settlements	(49,000,000)	(28,000,000)	(199,000,000)
Transfers into Level 3	0	0	0
Balance, end of period	0	(1,000,000)	4,000,000
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	5,000,000	6,000,000	15,000,000
Equity Derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Balance, beginning of period	(195,000,000)	(214,000,000)	(201,000,000)
Included in earnings	(94,000,000)	(84,000,000)	(86,000,000)
Purchases/originations	0	0	0
Settlements	121,000,000	103,000,000	73,000,000
Transfers into Level 3	0	0	0
Balance, end of period	(168,000,000)	(195,000,000)	(214,000,000)
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	$ (94,000,000)	$ (84,000,000)	$ (86,000,000)