Fair Value of Assets and Liabilities - Schedule 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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net  derivative liabilities
Beginning balance	$ (20)	$ (21)	$ (23)	$ (27)
Total net gains (losses) included in net income	0	(15)	0	(15)
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	2	2	5	8
Net transfers into (out of) Level 3	0	0	0	0
Ending balance	(18)	(34)	(18)	(34)
Net unrealized gains (losses) included in net income	0	(15)	0	(15)
Interest-only strips
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	19	28	13	25
Total net gains (losses) included in net income	(1)	(3)	(2)	(6)
Purchases	0	0	0	0
Sales	(8)	(5)	(10)	(8)
Settlements	0	0	0	0
Net transfers into (out of) Level 3	6	16	15	25
Ending balance	16	36	16	36
Net unrealized gains (losses) included in net income	0	(2)	(1)	(3)
Loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	14	21	26	22
Total net gains (losses) included in net income	0	0	0	0
Purchases	1	1	2	2
Sales	0	0	(13)	(2)
Settlements	(1)	0	(1)	0
Net transfers into (out of) Level 3	1	0	1	0
Ending balance	15	22	15	22
Net unrealized gains (losses) included in net income	$ 0	$ 0	$ 0	$ 0