Business Combination - Additional Information (Details) - Flagstar $ / shares in Units, $ in Millions	Dec. 01, 2022 USD ($) State Branch $ / shares
Business Acquisition [Line Items]
Business acquisition, share price \| $ / shares	$ 4.0151
Number of branches \| Branch	158
Number of states provides home loans \| State	50
Core deposit intangibles, estimated useful life	10 years
Bargain purchase gain \| $	$ 159

Business combination recognized identifiable assets acquired and liabilities assumed bargain purchase gain.

No definition available.

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Namespace Prefix:	nycb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of branches.

+ References

No definition available.

+ Details

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Namespace Prefix:	nycb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of states provides home loans.

+ References

No definition available.

+ Details

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Namespace Prefix:	nycb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI https://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

+ Details

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Period Type:	duration

- 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.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:
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