Loans and Leases - Quality of Loans Held for Investment (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 74,552	$ 84,619
Non-Accrual Loans	1,942	428
Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,204	250
Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	3,146	678
Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	71,406	83,941
Loans and Leases Held for Investment: | Multi-family
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	36,011	37,265
Non-Accrual Loans	794	138
Loans and Leases Held for Investment: | Multi-family | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	893	121
Loans and Leases Held for Investment: | Multi-family | Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,687	259
Loans and Leases Held for Investment: | Multi-family | Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	34,324	37,006
Loans and Leases Held for Investment: | Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	9,961	10,470
Non-Accrual Loans	753	128
Loans and Leases Held for Investment: | Commercial real estate | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	125	28
Loans and Leases Held for Investment: | Commercial real estate | Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	878	156
Loans and Leases Held for Investment: | Commercial real estate | Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	9,083	10,314
Loans and Leases Held for Investment: | One-to-four family first mortgage
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,790	6,061
Non-Accrual Loans	106	95
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	22	40
Loans and Leases Held for Investment: | One-to-four family first mortgage | Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	128	135
Loans and Leases Held for Investment: | One-to-four family first mortgage | Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	5,662	5,926
Loans and Leases Held for Investment: | Acquisition, development, and construction
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	3,217	2,912
Non-Accrual Loans	18	2
Loans and Leases Held for Investment: | Acquisition, development, and construction | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	54	2
Loans and Leases Held for Investment: | Acquisition, development, and construction | Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	72	4
Loans and Leases Held for Investment: | Acquisition, development, and construction | Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	3,145	2,908
Other loans held for investment | Commercial and industrial loans and lease financing
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	17,819	25,254
Non-Accrual Loans	247	43
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	100	37
Other loans held for investment | Commercial and industrial loans and lease financing | Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	347	80
Other loans held for investment | Commercial and industrial loans and lease financing | Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	17,472	25,174
Other loans held for investment | Other
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	1,754	2,657
Non-Accrual Loans	24	22
Other loans held for investment | Other | Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	10	22
Other loans held for investment | Other | Total Past Due Loans
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	34	44
Other loans held for investment | Other | Remaining
Financing Receivable, Recorded Investment, Past Due
Total Loans Receivable	$ 1,720	$ 2,613