Fair Value of Assets and Liabilities - Schedule of Changes In Level 3 Assets And Liabilities Measured At Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other expense	Other expense	Other expense
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other expense	Other expense
Level 3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ (27)	$ (23)	$ (14)
Total net gains (losses) included in net income	(15)	(23)	(19)
Purchases	0	0	0
Sales	0	0	0
Settlements	19	19	10
Repayments		0
Net transfers into (out of) Level 3	0	0	0
Ending balance	(23)	(27)	(23)
Net unrealized gains (losses) included in net income	(15)	(23)	(19)
Interest-only strips | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	25	38	32
Total net gains (losses) included in net income	(12)	(7)	3
Purchases	0	0	0
Sales	(54)	(76)	(68)
Settlements	0	0	0
Repayments		0
Net transfers into (out of) Level 3	54	70	71
Ending balance	13	25	38
Net unrealized gains (losses) included in net income	(1)	(2)	(2)
Loans held for sale | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	22	28	12
Total net gains (losses) included in net income	4	0	1
Purchases	3	2	10
Sales	(3)	(12)	(18)
Settlements	(2)	(2)	(3)
Repayments		(1)
Net transfers into (out of) Level 3	2	7	26
Ending balance	26	22	28
Net unrealized gains (losses) included in net income	$ 4	0	1
Loans held for investment | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		$ 0	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
Net unrealized gains (losses) included in net income			$ 0