Completed Acquisitions Other Information (Details) (USD $) In Millions, unless otherwise specified	Mar. 30, 2013
Other Information
Purchase Price Paid For Acquisitions Completed In A Prior Year	$ 4.0

Amount of cash payment during the period for acquisitions completed in a prior year. Includes contingent consideration and post closing adjustments.

No definition available.

Name:	tmo_PurchasePricePaidForAcquisitionsCompletedInPriorYear
Namespace Prefix:	tmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant