| Document and Entity Information | May 07, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | TERADYNE, INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000097210 |
| Current Fiscal Year End Date | --12-31 |
| Document Type | 8-K |
| Document Period End Date | May 7, 2021 |
| Entity Incorporation State Country Code | MA |
| Entity File Number | 001-06462 |
| Entity Tax Identification Number | 04-2272148 |
| Entity Address, Address Line One | 600 Riverpark Drive |
| Entity Address, City or Town | North Reading |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01864 |
| City Area Code | (978) |
| Local Phone Number | 370-2700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.125 per share |
| Trading Symbol | TER |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
