Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Feb. 16, 2022	Jul. 02, 2021
Cover [Abstract]
Amendment Flag	false
Document Type	10-K
Document Fiscal Year Focus	2021
Entity Central Index Key	0000097210
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Document Period End Date	Dec. 31, 2021
Entity Registrant Name	TERADYNE, INC.
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 16.9
Trading Symbol	TER
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	001-06462
Entity Incorporation, State or Country Code	MA
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
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		162,417,046
ICFR Auditor Attestation Flag	true
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Boston, Massachusetts