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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net  derivative liabilities
Beginning balance	$ (28)	$ (18)	$ (23)	$ (14)
Total net gains (losses) included in net income	(1)	0	(13)	(9)
Purchases		0	0	0
Sales	0	0	0	0
Settlements	9	2	16	7
Repayments	0		0
Net transfers into (out of) Level 3	0	0	0	0
Ending balance	(20)	(16)	(20)	(16)
Net unrealized gains (losses) included in net income	(1)	0	(13)	(9)
Interest-only strips
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	26	30	38	32
Total net gains (losses) included in net income	(2)	1	(5)	5
Purchases		0	0	0
Sales	(23)	(35)	(61)	(68)
Settlements	0	0	0	0
Repayments	0		0
Net transfers into (out of) Level 3	22	20	51	47
Ending balance	23	16	23	16
Net unrealized gains (losses) included in net income	(1)	0	(2)	0
Loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	34	25	28	12
Total net gains (losses) included in net income	0	0	0	2
Purchases		3	1	8
Sales	(14)	(8)	(14)	(18)
Settlements	0	0	(1)	(2)
Repayments	(1)		(1)
Net transfers into (out of) Level 3	1	4	7	22
Ending balance	20	24	20	24
Net unrealized gains (losses) included in net income	$ 0	0	$ 0	2
Loans held for investment
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance				16
Total net gains (losses) included in net income				0
Purchases				0
Sales				0
Settlements				(2)
Net transfers into (out of) Level 3				(14)
Ending balance		$ 0		0
Net unrealized gains (losses) included in net income				$ 0