Loans and Leases - Quality of Loans Held for Investment (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 66,592	$ 68,272
Non-Accrual Loans	3,280	2,615
Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,020	965
Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	62,292	64,692
Loans and Leases Held for Investment: \| Multi-family
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	33,437	34,093
Non-Accrual Loans	2,361	1,755
Loans and Leases Held for Investment: \| Multi-family \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	806	749
Loans and Leases Held for Investment: \| Multi-family \| Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	30,270	31,589
Loans and Leases Held for Investment: \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	11,510	11,836
Non-Accrual Loans	589	564
Loans and Leases Held for Investment: \| Commercial real estate \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	85	70
Loans and Leases Held for Investment: \| Commercial real estate \| Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	10,836	11,202
Loans and Leases Held for Investment: \| One-to-four family first mortgage
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,187	5,201
Non-Accrual Loans	77	70
Loans and Leases Held for Investment: \| One-to-four family first mortgage \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	28	25
Loans and Leases Held for Investment: \| One-to-four family first mortgage \| Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,082	5,106
Other loans held for investment \| Commercial and industrial loans and lease financing
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	14,742	15,376
Non-Accrual Loans	231	202
Other loans held for investment \| Commercial and industrial loans and lease financing \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	92	110
Other loans held for investment \| Commercial and industrial loans and lease financing \| Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	14,419	15,064
Other loans held for investment \| Other loan commitments
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,716	1,766
Non-Accrual Loans	22	24
Other loans held for investment \| Other loan commitments \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	9	11
Other loans held for investment \| Other loan commitments \| Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 1,685	$ 1,731

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

Reference 2: http://www.xbrl.org/2003/role/exampleRef
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