Fair Value Measurements - Level 3 Reconciliation (Details) - Recurring Fair Value Measurements - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Excess spread financing
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	$ 437	$ 509
Changes in fair value included in earnings	15	(4)
Purchases/additions(1)	0	0
Issuances	0	0
Sales/dispositions(2)	0	0
Repayments	0	(5)
Settlements	(49)	(54)
Other changes	0	0
Balance - end of period	403	446
Mortgage servicing rights financing
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	29	19
Changes in fair value included in earnings	11	2
Purchases/additions(1)	0	0
Issuances	0	0
Sales/dispositions(2)	0	0
Repayments	0	0
Settlements	0	0
Other changes	0	0
Balance - end of period	40	21
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	9,090	6,654
Changes in fair value included in earnings	(694)	(140)
Purchases/additions(1)	1,640	2,305
Issuances	267	219
Sales/dispositions(2)	(297)	(555)
Repayments	0	0
Settlements	0	0
Other changes	(29)	(21)
Balance - end of period	10,035	8,504
Mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	81	74
Changes in fair value included in earnings	2	3
Purchases/additions(1)	95	130
Issuances	0	0
Sales/dispositions(2)	(110)	(105)
Repayments	(3)	(3)
Settlements	0	0
Other changes	0	(2)
Balance - end of period	65	101
Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	8	45
Changes in fair value included in earnings	0	(37)
Purchases/additions(1)	0	0
Issuances	0	0
Sales/dispositions(2)	0	0
Repayments	0	0
Settlements	0	0
Other changes	0	0
Balance - end of period	8	8
IRLCs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	21	22
Changes in fair value included in earnings	20	0
Purchases/additions(1)	0	0
Issuances	0	0
Sales/dispositions(2)	0	0
Repayments	0	0
Settlements	0	0
Other changes	0	0
Balance - end of period	$ 41	$ 22