| Document and Entity Information Document | Aug. 01, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Aug. 1, 2019 |
| Entity Registrant Name | TERADATA CORP /DE/ |
| Entity File Number | 001-33458 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 75-3236470 |
| Entity Address, Address Line One | 17095 Via Del Campo |
| Entity Address, City or Town | San Diego |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92127 |
| City Area Code | 866 |
| Local Phone Number | 548-8348 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | TDC |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000816761 |
| Amendment Flag | false |
