Loans and Leases - Collateral (Details) - Real Property - Asset Pledged as Collateral $ in Millions	Sep. 30, 2025 USD ($)
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	$ 3,055
Loans and leases held for investment: | Multi-family
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	2,435
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	545
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	59
Other loans held for investment | Commercial and Industrial
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total collateral-dependent loans held for investment	$ 16