Loans and Leases - Collateral (Details) - Asset pledged as collateral $ in Millions	Jun. 30, 2024 USD ($)
Real Property
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	$ 1,790
Real Property | Loans and Leases Held for Investment: | Multi-family
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	896
Real Property | Loans and Leases Held for Investment: | Commercial real estate
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	769
Real Property | Loans and Leases Held for Investment: | One-to-four family first mortgage
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	106
Real Property | Loans and Leases Held for Investment: | Acquisition, development, and construction
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	19
Real Property | Other loans held for investment | Commercial and industrial
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	0
Other
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	240
Other | Loans and Leases Held for Investment: | Multi-family
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	0
Other | Loans and Leases Held for Investment: | Commercial real estate
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	0
Other | Loans and Leases Held for Investment: | One-to-four family first mortgage
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	0
Other | Loans and Leases Held for Investment: | Acquisition, development, and construction
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	0
Other | Other loans held for investment | Commercial and industrial
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	$ 240