Fair Value Measurements - Level 3 Reconciliation (Details) - Recurring Fair Value Measurements - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Excess spread financing
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	$ 386	$ 437
Changes in fair value included in earnings	(5)	0
Purchases/additions(1)	0	0
Issuances	0	0
Sales/dispositions(2)	0	0
Repayments	0	0
Settlements	(15)	(17)
Other changes	0	0
Balance - end of period	366	420
Mortgage servicing rights financing
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	32	29
Changes in fair value included in earnings	0	6
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	32	35
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	11,736	9,090
Changes in fair value included in earnings	(505)	10
Purchases/additions(1)	106	663
Issuances	164	64
Sales/dispositions(2)	(164)	(42)
Repayments	0	0
Settlements	0	0
Other changes	(8)	(11)
Balance - end of period	11,345	9,796
Mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	60	81
Changes in fair value included in earnings	(4)	(2)
Purchases/additions(1)	52	28
Issuances	0	0
Sales/dispositions(2)	(27)	(22)
Repayments	(1)	(2)
Settlements	0	0
Other changes	0	1
Balance - end of period	80	82
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period		8
Changes in fair value included in earnings		0
Purchases/additions(1)		0
Issuances		0
Sales/dispositions(2)		0
Repayments		0
Settlements		0
Other changes		0
Balance - end of period		8
Forward MBS trades
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	6
Changes in fair value included in earnings	2
Purchases/additions(1)	0
Issuances	0
Sales/dispositions(2)	0
Repayments	0
Settlements	0
Other changes	0
Balance - end of period	8
Interest Rate Lock Commitments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - beginning of period	22	21
Changes in fair value included in earnings	16	6
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	$ 38	$ 27