Loans Held-for-Investment - Changes in ALLL by Class of Loan (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ 131	$ 241	$ 154	$ 252
(Benefit) provision	(8)	(38)	(10)	(62)
Charge-offs	(3)	(2)	(26)	(7)
Recoveries	2	1	4	19
Ending allowance balance	122	202	122	202
Consumer loans | Residential first mortgage loans
Allowance for Loan Losses [Roll Forward]
Beginning balance	43	45	40	49
(Benefit) provision	(10)	4	(6)	1
Charge-offs	0	(1)	(1)	(3)
Recoveries	0	0	0	1
Ending allowance balance	33	48	33	48
Consumer loans | Home equity
Allowance for Loan Losses [Roll Forward]
Beginning balance	16	20	14	25
(Benefit) provision	5	(4)	6	(7)
Charge-offs	0	0	0	(1)
Recoveries	0	1	1	0
Ending allowance balance	21	17	21	17
Consumer loans | Other consumer
Allowance for Loan Losses [Roll Forward]
Beginning balance	34	33	36	39
(Benefit) provision	(2)	6	(3)	(1)
Charge-offs	(3)	(1)	(5)	(2)
Recoveries	2	0	3	2
Ending allowance balance	31	38	31	38
Commercial loans | Commercial real estate
Allowance for Loan Losses [Roll Forward]
Beginning balance	22	84	28	84
(Benefit) provision	0	(26)	(6)	(26)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending allowance balance	22	58	22	58
Commercial loans | Commercial and industrial
Allowance for Loan Losses [Roll Forward]
Beginning balance	13	55	32	51
(Benefit) provision	(2)	(17)	(1)	(28)
Charge-offs	0	0	(20)	(1)
Recoveries	0	0	0	16
Ending allowance balance	11	38	11	38
Commercial loans | Warehouse lending
Allowance for Loan Losses [Roll Forward]
Beginning balance	3	4	4	4
(Benefit) provision	1	(1)	0	(1)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending allowance balance	$ 4	$ 3	$ 4	$ 3