v3.25.4

Document and Entity Information	Jan. 30, 2026
Document Information [Line Items]
Document Period End Date	Jan. 30, 2026
Document Type	8-K
Amendment Flag	false
Entity Registrant Name	Flagstar Bank, National Association
Entity Central Index Key	0000910073
Entity Incorporation, State or Country Code	X1
Entity Tax Identification Number	38-2734984
Entity Address, City or Town	Hicksville,
Entity Address, Postal Zip Code	11801
City Area Code	516
Local Phone Number	683-4100
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Entity Emerging Growth Company	false
Entity File Number	1-31565
Entity Address, Address Line One	102 Duffy Avenue,
Entity Address, State or Province	NY
Common Stock
Document Information [Line Items]
Security Exchange Name	NYSE
Title of 12(b) Security	Common stock, $0.01 par value per share
Trading Symbol	FLG
Bifurcated Option Note Unit Securities [Member]
Document Information [Line Items]
Security Exchange Name	NYSE
Title of 12(b) Security	Bifurcated Option Note Unit Securities SM
Trading Symbol	FLG PRU
Fixed To Floating Rate Series A Noncumulative Perpetual Preferred Stock [Member]
Document Information [Line Items]
Security Exchange Name	NYSE
Title of 12(b) Security	Depositary Shares each representing a 1/40th interest in a share of Fixed-to-Floating Rate Series A Noncumulative Perpetual Preferred Stock
Trading Symbol	FLG PRA

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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.

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For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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Address Line 1 such as Attn, Building Name, Street Name

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Name of the state or province.

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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Local phone number for entity.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Exchange Act
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Trading symbol of an instrument as listed on an exchange.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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FLAGSTAR BANK, NATIONAL ASSOCIATION 8-K