Loans and Leases - Quality of Loans Held for Investment (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 83,995	$ 69,001
Non- Accrual Loans	434	141
Loans 90 Days or More Delinquent and Still Accruing Interest	0	0
Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	169	70
Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	603	211
Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	83,392	68,790
Mortgage Loans:
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	56,976	54,473
Mortgage Loans: \| Multi-family
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	37,698	38,130
Non- Accrual Loans	102	13
Mortgage Loans: \| Multi-family \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	60	34
Mortgage Loans: \| Multi-family \| Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	162	47
Mortgage Loans: \| Multi-family \| Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	37,536	38,083
Mortgage Loans: \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	10,486	8,526
Non- Accrual Loans	157	20
Mortgage Loans: \| Commercial real estate \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	26	2
Mortgage Loans: \| Commercial real estate \| Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	183	22
Mortgage Loans: \| Commercial real estate \| Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	10,303	8,504
Mortgage Loans: \| One-to-four family first mortgage
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,882	5,821
Non- Accrual Loans	90	92
Mortgage Loans: \| One-to-four family first mortgage \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	19	21
Mortgage Loans: \| One-to-four family first mortgage \| Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	109	113
Mortgage Loans: \| One-to-four family first mortgage \| Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,773	5,708
Mortgage Loans: \| Acquisition, development, and construction
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	2,910	1,996
Non- Accrual Loans	1	0
Mortgage Loans: \| Acquisition, development, and construction \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1	0
Mortgage Loans: \| Acquisition, development, and construction \| Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	2	0
Mortgage Loans: \| Acquisition, development, and construction \| Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	2,908	1,996
Other Loans:
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	27,019	14,528
Other Loans: \| Commercial and industrial loans and lease financing
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	24,423	12,276
Non- Accrual Loans	65	3
Other Loans: \| Commercial and industrial loans and lease financing \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	43	2
Other Loans: \| Commercial and industrial loans and lease financing \| Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	108	5
Other Loans: \| Commercial and industrial loans and lease financing \| Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	24,315	12,271
Other Loans: \| Other
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	2,596	2,252
Non- Accrual Loans	19	13
Other Loans: \| Other \| Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	20	11
Other Loans: \| Other \| Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	39	24
Other Loans: \| Other \| Current Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 2,557	$ 2,228

Amortized cost excluding accrued interest, of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

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