Loans and Leases - Portfolio of Loans Held for Investment by Credit Quality Indicator (Details) - USD ($) $ in Millions		Jun. 30, 2022		Dec. 31, 2021
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans	[1]	$ 48,485		$ 45,681
Multi-Family
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		36,772		34,603
Multi-Family | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		35,073		33,011
Multi-Family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		1,008		981
Multi-Family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		691		611
Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		6,712		6,698
Commercial Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		5,776		5,874
Commercial Real Estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		695		643
Commercial Real Estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		241		181
One-to-Four Family
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		129		160
One-to-Four Family | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		113		137
One-to-Four Family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		8		14
One-to-Four Family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		8		9
Acquisition, Development, and Construction
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		195		209
Acquisition, Development, and Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		191		204
Acquisition, Development, and Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		4		5
Mortgage Receivable
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans	[1]	43,808		41,670
Mortgage Receivable | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		41,153		39,226
Mortgage Receivable | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		1,715		1,643
Mortgage Receivable | Substandard
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		940		801
Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans	[3]	4,671	[2]	4,006	[4]
Commercial and Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		4,667	[2]	3,959	[4]
Commercial and Industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans	[4]			2
Commercial and Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		4	[2]	45	[4]
Other
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		6		5
Other | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		6		5
Total Other Loans
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		4,677		4,011
Total Other Loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		4,673		3,964
Total Other Loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans				2
Total Other Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Non-Covered Loans		$ 4		$ 45

[1] Excludes accrued interest receivable of $197 million and $199 million at June 30, 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 $4.1 billion and $3.5 billion, respectively, at June 30, 2022 and December 31, 2021, and other C&I loans of $548 million and $527 million, respectively, at June 30, 2022 and December 31, 2021.

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