Allowance for Credit Losses on Loans and Leases - Activity in the Allowance for Loan and Lease Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 1,168	$ 1,215	$ 1,201	$ 992	$ 992
Charge-offs	(140)	(354)	(264)	(445)
Recoveries	23	5	32	14
Provision for (recovery of) credit losses on loans and leases	55	402	137	707
Balance, end of period	1,106	1,268	1,106	1,268	1,201
Loans and leases held for investment: | Multi-family
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	609	469	639	307	307
Charge-offs	(105)	(76)	(185)	(87)	(308)
Recoveries	9	0	9	1
Provision for (recovery of) credit losses on loans and leases	25	225	75	397
Balance, end of period	538	618	538	618	639
Loans and leases held for investment: | Commercial Real Estate
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	289	482	304	402	402
Charge-offs	(20)	(237)	(22)	(301)	(466)
Recoveries	7	0	7	0
Provision for (recovery of) credit losses on loans and leases	42	126	29	270
Balance, end of period	318	371	318	371	304
Loans and leases held for investment: | One-to-Four Family First Mortgage
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	37	42	39	47	47
Charge-offs	(1)	(1)	(2)	(1)	(8)
Recoveries	0	0	0	0
Provision for (recovery of) credit losses on loans and leases	(3)	(1)	(4)	(6)
Balance, end of period	33	40	33	40	39
Loans and leases held for investment: | Commercial and Industrial
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			(41)		(136)
Other
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	66	65	68	102	102
Charge-offs	(7)	(5)	(14)	(10)
Recoveries	3	1	6	2
Provision for (recovery of) credit losses on loans and leases	(5)	5	(3)	(28)
Balance, end of period	57	66	57	66	68
Other | Commercial and Industrial
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	167	157	151	134	134
Charge-offs	(7)	(35)	(41)	(46)
Recoveries	4	4	10	11
Provision for (recovery of) credit losses on loans and leases	(4)	47	40	74
Balance, end of period	$ 160	$ 173	$ 160	$ 173	$ 151