Loans and Leases - Quality of Loans Held for Investment (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 64,121	$ 68,272
Non-Accrual Loans	3,180	2,615
Current
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	60,337	64,692
Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	604	965
Loans and leases held for investment: | Multi-family
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	31,932	34,093
Non-Accrual Loans	2,388	1,755
Loans and leases held for investment: | Multi-family | Current
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	29,152	31,589
Loans and leases held for investment: | Multi-family | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	392	749
Loans and leases held for investment: | Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	10,636	11,836
Non-Accrual Loans	563	564
Loans and leases held for investment: | Commercial real estate | Current
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	9,958	11,202
Loans and leases held for investment: | Commercial real estate | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	115	70
Loans and leases held for investment: | One-to-four family first mortgage
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,445	5,201
Non-Accrual Loans	81	70
Loans and leases held for investment: | One-to-four family first mortgage | Current
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,334	5,106
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	30	25
Other loans held for investment | Commercial and industrial loans and lease financing
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	14,426	15,376
Non-Accrual Loans	123	202
Other loans held for investment | Commercial and industrial loans and lease financing | Current
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	14,265	15,064
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	38	110
Other loans held for investment | Other loan commitments
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,682	1,766
Non-Accrual Loans	25	24
Other loans held for investment | Other loan commitments | Current
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,628	1,731
Other loans held for investment | Other loan commitments | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 29	$ 11