Document and Entity Information	9 Months Ended
	Sep. 30, 2012	Oct. 27, 2012
Document Information
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Trading Symbol	TDC
Entity Registrant Name	TERADATA CORP /DE/
Entity Central Index Key	0000816761
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		169,100,000