Loans and Leases - Composition of Loan and Lease Portfolio Held for Investment (Details) - USD ($) $ in Millions		Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans	[1]	$ 69,001		$ 45,738
Non-Covered Loans, Percentage	[1]	100.00%		100.00%
Allowance for credit losses on loans and leases		$ (393)		$ (199)		$ (194)
Total loans and leases held for investment, net		68,608		45,539
Loans held for sale, at fair value		1,115
Total loans and leases, net		69,723		45,539
Multi-Family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 38,130		$ 34,628
Non-Covered Loans, Percentage		55.30%		75.70%
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 8,526		$ 6,701
Non-Covered Loans, Percentage		12.40%		14.70%
One-to-Four Family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 5,821		$ 160
One-to-Four Family First Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 5,821		$ 160
Non-Covered Loans, Percentage		8.40%		0.30%
Acquisition, Development, and Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 1,996		$ 209
Non-Covered Loans, Percentage		2.80%		0.50%
Mortgage Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans	[1]	$ 54,473		$ 41,698
Non-Covered Loans, Percentage	[1]	78.90%		91.20%
Allowance for credit losses on loans and leases		$ (290)		$ (178)		$ (176)
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans	[3]	$ 12,276	[2]	$ 4,034	[4]
Non-Covered Loans, Percentage	[3]	17.80%		7.20%
Commercial and Industrial | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 10,597		$ 2,238
Non-Covered Loans, Percentage		15.40%		3.20%
Lease Financing, Unearned Income
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 1,679		$ 1,796
Non-Covered Loans, Percentage		2.40%		3.90%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 2,252		$ 6
Non-Covered Loans, Percentage		3.30%		0.00%
Total Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 14,528		$ 4,040
Total Other Loans | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Covered Loans		$ 14,528		$ 4,040
Non-Covered Loans, Percentage		21.10%		7.20%

[1] Excludes accrued interest receivable of $292 million and $199 million at December 31, 2022 and December 31, 2021, respectively, which is included in other assets in the Consolidated Statements of Condition.

[2] Includes lease financing receivables, all of which were classified as Pass.

[3] Includes specialty finance loans and leases of $4.4 billion and $3.5 billion, respectively, at December 31, 2022 and December 31, 2021.

[4] Includes lease financing receivables, all of which were classified as Pass.