Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 19, 2020	Jun. 30, 2019
Document Information [Line Items]
Amendment Flag	false
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Document Period End Date	Dec. 31, 2019
Entity Central Index Key	0000910073
Current Fiscal Year End Date	--12-31
Entity Registrant Name	NEW YORK COMMUNITY BANCORP INC
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Well-known Seasoned Issuer	Yes
Entity Small Business	false
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Public Float			$ 4.5
Entity Common Stock, Shares Outstanding		467,301,496
Entity Interactive Data Current	Yes
Entity File Number	1-31565
Entity Incorporation, State or Country Code	DE
City Area Code	516
Entity Tax Identification Number	06-1377322
Local Phone Number	683-4100
Entity Address, Address Line One	615 Merrick Avenue
Entity Address, City or Town	Westbury
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	11590
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock
Security Exchange Name	NYSE
Trading Symbol	NYCB
Bifurcated Option Note Unit SecuritiES [Member]
Document Information [Line Items]
Title of 12(b) Security	Bifurcated Option Note Unit SecuritiESSM
Security Exchange Name	NYSE
Trading Symbol	NYCB PU
Fixed to Floating Rate Series A Noncumulative Perpetual Preferred Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares each representing
Security Exchange Name	NYSE
Trading Symbol	NYCB PA