Allowance for Credit Losses on Loans and Leases - Summary of Additional Information about Nonaccrual Loans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance, Recorded Investment	$ 125	$ 29
Impaired loans with no related allowance, Interest Income Recognized	1	1
Impaired loans with an allowance recorded, Recorded Investment	16	4
Impaired loans with an allowance recorded, Related Allowance	14
Total impaired loans, Recorded Investment	141	33
Total impaired loans, Related Allowance	14
Total impaired loans, Interest Income Recognized	1	1
Multi-Family
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance, Recorded Investment	13	9
Impaired loans with no related allowance, Interest Income Recognized		1
Impaired loans with an allowance recorded, Recorded Investment		1
Total impaired loans, Recorded Investment	13	10
Total impaired loans, Interest Income Recognized		1
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance, Recorded Investment	19	14
Impaired loans with no related allowance, Interest Income Recognized	1
Impaired loans with an allowance recorded, Recorded Investment	1	2
Total impaired loans, Recorded Investment	20	16
Total impaired loans, Interest Income Recognized	1
One-to-Four Family First Mortgage
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance, Recorded Investment	90
Impaired loans with an allowance recorded, Recorded Investment	2	1
Total impaired loans, Recorded Investment	92	1
Other loans
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance, Recorded Investment	3	6
Impaired loans with an allowance recorded, Recorded Investment	13
Impaired loans with an allowance recorded, Related Allowance	14
Total impaired loans, Recorded Investment	16	$ 6
Total impaired loans, Related Allowance	$ 14

Impaired financing receivable with related allowance.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(2)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524

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- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (a)(3)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

+ References

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- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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