Accounting Policies	3 Months Ended
Accounting Policies	Apr. 01, 2012
Accounting Policies [Abstract]
Accounting Policies	B. Accounting Policies Basis of Presentation The condensed consolidated interim financial statements include the accounts of Teradyne and its subsidiaries. All significant intercompany balances and transactions have been eliminated. These interim financial statements are unaudited and reflect all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of such interim financial statements. Certain prior year's amounts were reclassified to conform to the current year presentation. The December 31, 2011 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne's Annual Report on Form 10-K, filed with the SEC on February 29, 2012 for the year ended December 31, 2011. Preparation of Financial Statements and Use of Estimates The preparation of consolidated financial statements requires management to make estimates and judgments that affect the amounts reported in the financial statements. Actual results may differ significantly from these estimates.

The entire disclosure for all significant accounting policies of the reporting entity.