Fair Value of Assets and Liabilities - Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net derivative liabilities
Beginning balance	$ (18)	$ (21)	$ (23)	$ (14)
Total net gains (losses) included in net income	(12)	0	(12)	(9)
Purchases		0	0	0
Sales		0	0	0
Settlements	2	3	7	5
Net transfers into (out of) Level 3	0	0	0	0
Ending balance	(28)	(18)	(28)	(18)
Net unrealized gains (losses) included in net income	(12)	0	(12)	(9)
Interest-only strips
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	12	22	38	32
Total net gains (losses) included in net income	(3)	(1)	(3)	4
Purchases		0	0	0
Sales		(6)	(37)	(33)
Settlements	0	0	0	0
Net transfers into (out of) Level 3	17	15	28	27
Ending balance	26	30	26	30
Net unrealized gains (losses) included in net income	(3)	(1)	(4)	1
Loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	32	12	28	12
Total net gains (losses) included in net income	0	1	0	2
Purchases		5	1	5
Sales		(10)	0	(10)
Settlements	0	(1)	(1)	(2)
Net transfers into (out of) Level 3	2	18	6	18
Ending balance	34	25	34	25
Net unrealized gains (losses) included in net income	$ 0	1	$ 0	2
Loans held for investment
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		17		16
Total net gains (losses) included in net income		0		0
Purchases		0		0
Sales		0		0
Settlements		0		(2)
Net transfers into (out of) Level 3		(17)		(14)
Ending balance		0		0
Net unrealized gains (losses) included in net income		$ 0		$ 0

Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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Amount of unrealized gain (loss) recognized in income for derivative asset (liability) after deduction of derivative liability (asset), measured at fair value using unobservable input (level 3) and still held.

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Amount of gain (loss) recognized in income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3).

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Amount of purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sales of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfers of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) into (out of) level 3 of the fair value hierarchy.

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