Document And Entity Information	6 Months Ended
Jul. 01, 2011	Jul. 29, 2011
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	true
Amendment Description	This Amendment No. 2 to Form 10-Q for the quarterly period ended July 1, 2011, amends the Quarterly Report on Form 10-Q/A Amendment No.1 filed with the SEC on December 5, 2011. The filing agent inadvertently used the XBRL interactive data file for Amendment No. 1 on Form 10-Q/A for the quarterly period ended September 30, 2011 instead of the XBRL interactive data file for Amendment No. 1 on Form 10-Q/A for the quarterly period ended July 1, 2011 when uploading the file. No changes have been made to Amendment No. 1 on Form 10-Q/A, only the XBRL interactive data filed in conjunction with this Amendment No. 2. This Amendment No. 2 continues to speak as of the date of the filing of the original Quarterly Report on Form 10-Q/A Amendment No. 1, and we have not updated the disclosures contained herein to reflect any events that occurred at a later date. Accordingly, this Amendment No. 2 should be read in conjunction with other subsequent filings we have made with the SEC since the date thereof.
Document Period End Date	Jul. 01, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
Trading Symbol	tlab
Entity Registrant Name	TELLABS INC
Entity Central Index Key	0000317771
Current Fiscal Year End Date	--12-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		364,884,602

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