Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2019	Oct. 31, 2019	Mar. 31, 2019
Document Documentand Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-27038
Entity Registrant Name	NUANCE COMMUNICATIONS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3156479
Entity Address, Address Line One	1 Wayside Road
Entity Address, Postal Zip Code	01803
Entity Address, City or Town	Burlington,
Entity Address, State or Province	MA
City Area Code	781
Local Phone Number	565-5000
Title of 12(b) Security	Common stock, $0.001 par value
Trading Symbol	NUAN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 3,400,000,000
Entity Common Stock, Shares Outstanding		282,635,321
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement to be delivered to stockholders in connection with the registrant’s 2020 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K.
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001002517
Current Fiscal Year End Date	--09-30