Loans and Leases - Quality of Loans Held for Investment (Details) - USD ($) $ in Millions		Jun. 30, 2021		Dec. 31, 2020		Jun. 30, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Receivable		$ 43,518		$ 42,822
Multi-Family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Receivable		32,540		32,236
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Receivable		6,813		6,836
One-to-Four Family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Receivable		190		236
Acquisition, Development, and Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Receivable		187		90
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual Loans		2				$ 6
Total Loans Receivable	[2]	3,776	[1]	3,417	[3]
Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Receivable		12		7
Non-Covered Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		67		54
Non- Accrual Loans		32		38
Current Loans		43,451		42,768
Total Loans Receivable		43,518		42,822
Non-Covered Loans | Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		35		16
Non-Covered Loans | Multi-Family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		18		8
Non- Accrual Loans		9		4
Current Loans		32,522		32,228
Total Loans Receivable		32,540		32,236
Non-Covered Loans | Multi-Family | Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		9		4
Non-Covered Loans | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		27		22
Non- Accrual Loans		12		12
Current Loans		6,786		6,814
Total Loans Receivable		6,813		6,836
Non-Covered Loans | Commercial Real Estate | Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		15		10
Non-Covered Loans | One-to-Four Family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		2		4
Non- Accrual Loans		2		2
Current Loans		188		232
Total Loans Receivable		190		236
Non-Covered Loans | One-to-Four Family | Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans				2
Non-Covered Loans | Acquisition, Development, and Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans		187		90
Total Loans Receivable		187		90
Non-Covered Loans | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		11	[4],[5]	20	[6],[7]
Non- Accrual Loans	[6],[7]			20
Current Loans		3,765	[4],[5]	3,397	[6],[7]
Total Loans Receivable		3,776	[4],[5]	3,417	[6],[7]
Non-Covered Loans | Commercial and Industrial | Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	[4],[5]	11
Non-Covered Loans | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		9
Non- Accrual Loans		9
Current Loans		3		7
Total Loans Receivable		$ 12		$ 7

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

[2] Includes specialty finance loans and leases of $3.2 billion and $3.0 billion, respectively, at June 30, 2021 and December 31, 2020, and other C&I loans of $555 million and $393 million, respectively, at J

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

[4] Includes $9 million of taxi medallion-related loans that were 90 days or more past due. There were no taxi medallion-related loans that were 30 to 89 days past due.

[5] Includes lease financing receivables, all of which were current.

[6] Includes $19 million of taxi medallion-related loans that were 90 days or more past due. There were no taxi medallion-related loans that were 30 to 89 days past due.

[7] Includes lease financing receivables, all of which were current.