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, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Net  derivative liabilities
Beginning balance	$ (21)	$ (18)	$ (27)	$ (23)
Total net gains (losses) included in net income	(15)	(12)	(15)	(12)
Purchases	0		0	0
Sales	0		0	0
Settlements	2	2	8	7
Net transfers into (out of) Level 3	0	0	0	0
Ending balance	(34)	(28)	(34)	(28)
Net unrealized gains (losses) included in net income	(15)	(12)	(15)	(12)
Interest-only strips
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	28	12	25	38
Total net gains (losses) included in net income	(3)	(3)	(6)	(3)
Purchases	0		0	0
Sales	(5)		(8)	(37)
Settlements	0	0	0	0
Net transfers into (out of) Level 3	16	17	25	28
Ending balance	36	26	36	26
Net unrealized gains (losses) included in net income	(2)	(3)	(3)	(4)
Loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	21	32	22	28
Total net gains (losses) included in net income	0	0	0	0
Purchases	1		2	1
Sales	0		(2)	0
Settlements	0	0	0	(1)
Net transfers into (out of) Level 3	0	2	0	6
Ending balance	22	34	22	34
Net unrealized gains (losses) included in net income	$ 0	$ 0	$ 0	$ 0