v3.25.1
Document and Entity Information
Jun. 04, 2025
Document Information [Line Items]  
Document Period End Date Jun. 04, 2025
Document Type 8-K
Amendment Flag false
Entity Registrant Name FLAGSTAR FINANCIAL, INC.
Entity Central Index Key 0000910073
Entity Incorporation, State or Country Code DE
Entity Tax Identification Number 06-1377322
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