Loans and Leases - Loan Modifications (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 34	$ 262
Loans held for investment | Multi-family
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 2	$ 122
Percent of Total Loan class	0.01%	1.17%
Loans held for investment | Commercial real estate
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 12	$ 103
Percent of Total Loan class	0.14%	0.98%
Loans held for investment | One-to-four family first mortgage
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 16	$ 14
Percent of Total Loan class	0.29%	0.23%
Other loans held for investment | Commercial and industrial
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 4	$ 21
Percent of Total Loan class	0.03%	0.08%
Other loans held for investment | Other Consumer
Financing Receivable, Modified [Line Items]
Amortized Cost		$ 2
Percent of Total Loan class		0.08%
Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 10	$ 227
Interest Rate Reduction | Loans held for investment | Multi-family
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 2	$ 122
Interest Rate Reduction | Loans held for investment | Multi-family | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	8.08%	7.45%
Interest Rate Reduction | Loans held for investment | Multi-family | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	6.00%	6.02%
Interest Rate Reduction | Loans held for investment | Commercial real estate
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 8	$ 102
Weighted-average Term (in years)	3 months
Interest Rate Reduction | Loans held for investment | Commercial real estate | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	8.13%	8.83%
Interest Rate Reduction | Loans held for investment | Commercial real estate | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	6.95%	4.56%
Interest Rate Reduction | Loans held for investment | One-to-four family first mortgage
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 0	$ 3
Weighted-average Term (in years)	11 years 3 months 7 days
Interest Rate Reduction | Loans held for investment | One-to-four family first mortgage | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	4.73%	6.08%
Interest Rate Reduction | Loans held for investment | One-to-four family first mortgage | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	3.80%	4.79%
Interest Rate Reduction | Loans held for investment | Commercial and industrial
Financing Receivable, Modified [Line Items]
Weighted-average Term (in years)	8 months 12 days	6 months 29 days
Interest Rate Reduction | Loans held for investment | Commercial and industrial | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	7.73%	8.44%
Interest Rate Reduction | Loans held for investment | Commercial and industrial | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	6.10%	8.08%
Interest Rate Reduction | Loans held for investment | Other Consumer
Financing Receivable, Modified [Line Items]
Weighted-average Term (in years)	2 years 1 month 6 days
Interest Rate Reduction | Loans held for investment | Other Consumer | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	10.69%	9.09%
Interest Rate Reduction | Loans held for investment | Other Consumer | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	3.71%	4.82%
Interest Rate Reduction | Other loans held for investment | Commercial and industrial
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 0	$ 0
Interest Rate Reduction | Other loans held for investment | Other Consumer
Financing Receivable, Modified [Line Items]
Amortized Cost		0
Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost	15	25
Term Extension | Loans held for investment | Multi-family
Financing Receivable, Modified [Line Items]
Amortized Cost	0	0
Term Extension | Loans held for investment | Commercial real estate
Financing Receivable, Modified [Line Items]
Amortized Cost	4	1
Term Extension | Loans held for investment | One-to-four family first mortgage
Financing Receivable, Modified [Line Items]
Amortized Cost	7	5
Term Extension | Other loans held for investment | Commercial and industrial
Financing Receivable, Modified [Line Items]
Amortized Cost	4	19
Term Extension | Other loans held for investment | Other Consumer
Financing Receivable, Modified [Line Items]
Amortized Cost		0
Combination - Interest Rate Reduction & Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost	8	10
Combination - Interest Rate Reduction & Term Extension | Loans held for investment | Multi-family
Financing Receivable, Modified [Line Items]
Amortized Cost	0	0
Combination - Interest Rate Reduction & Term Extension | Loans held for investment | Commercial real estate
Financing Receivable, Modified [Line Items]
Amortized Cost	0	0
Combination - Interest Rate Reduction & Term Extension | Loans held for investment | One-to-four family first mortgage
Financing Receivable, Modified [Line Items]
Amortized Cost	8	6
Combination - Interest Rate Reduction & Term Extension | Other loans held for investment | Commercial and industrial
Financing Receivable, Modified [Line Items]
Amortized Cost	0	2
Combination - Interest Rate Reduction & Term Extension | Other loans held for investment | Other Consumer
Financing Receivable, Modified [Line Items]
Amortized Cost		2
Principal Forgiveness
Financing Receivable, Modified [Line Items]
Amortized Cost	1	0
Principal Forgiveness | Loans held for investment | Multi-family
Financing Receivable, Modified [Line Items]
Amortized Cost	0	0
Principal Forgiveness | Loans held for investment | Commercial real estate
Financing Receivable, Modified [Line Items]
Amortized Cost	0	0
Principal Forgiveness | Loans held for investment | One-to-four family first mortgage
Financing Receivable, Modified [Line Items]
Amortized Cost	1	0
Principal Forgiveness | Other loans held for investment | Commercial and industrial
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 0	0
Principal Forgiveness | Other loans held for investment | Other Consumer
Financing Receivable, Modified [Line Items]
Amortized Cost		$ 0