| Document and Entity Information | Dec. 01, 2022 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | NEW YORK COMMUNITY BANCORP INC |
| Amendment Flag | true |
| Entity Central Index Key | 0000910073 |
| Document Type | 8-K/A |
| Document Period End Date | Dec. 01, 2022 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-31565 |
| Entity Tax Identification Number | 06-1377322 |
| Entity Address, Address Line One | 102 Duffy Avenue |
| Entity Address, City or Town | Hicksville |
| Entity Address, State or Province | NY |
| 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 |
| Amendment Description | On December 1, 2022, New York Community Bancorp, Inc., a Delaware corporation (“NYCB”), filed a Current Report on Form 8-K (the “Original Report”) to report that, effective as of December 1, 2022, before the opening of business, NYCB completed its acquisition of Flagstar Bancorp, Inc., a Michigan corporation (“Flagstar”), pursuant to the Agreement and Plan of Merger, dated April 24, 2021, by and among NYCB, 615 Corp., a Delaware corporation and a direct, wholly-owned subsidiary of NYCB (“Merger Sub”), and Flagstar, as amended by Amendment No. 1 to the Original Agreement, dated as of April 26, 2022 (“Amendment No. 1”), by and among NYCB, Merger Sub and Flagstar, and as further amended by Amendment No. 2 to the Original Agreement, dated as of October 27, 2022 (“Amendment No. 2,” and the Original Agreement, as amended by Amendment No. 1 and Amendment No. 2, the “Merger Agreement”), by and among NYCB, Merger Sub and Flagstar. At the closing, (i) Merger Sub merged with and into Flagstar (the “Merger”), with Flagstar as the surviving entity, and (ii) immediately thereafter, Flagstar merged with and into NYCB, with NYCB as the surviving entity. This amendment to the Original Report (the “Amendment”) is being filed to provide the financial statements and pro forma financial information required by Item 9.01 of Form 8-K. |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $0.01 par value per share |
| Trading Symbol | NYCB |
| Security Exchange Name | NYSE |
| Bifurcated Option Notes Unit Securities [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Bifurcated Option Note Unit SecuritiES SM |
| Trading Symbol | NYCB PU |
| Security Exchange Name | NYSE |
| Fixed To Floating Rate Series A Noncumulative Perpetual Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Fixed-to-Floating Rate Series A Noncumulative Perpetual Preferred Stock, $0.01 par value |
| Trading Symbol | NYCB PA |
| Security Exchange Name | NYSE |
