Document and Entity Information	6 Months Ended
	Jun. 30, 2020 shares
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	1-8729
Entity Registrant Name	UNISYS CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	38-0387840
Entity Address, Address Line One	801 Lakeview Drive, Suite 100
Entity Address, City or Town	Blue Bell
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19422
City Area Code	215
Local Phone Number	986-4011
Title of 12(b) Security	Common Stock, par value $.01
Trading Symbol	UIS
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	63,017,239
Entity Central Index Key	0000746838
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false