Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 30, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Restructuring and Related Costs, Non-Cash Costs	$ 0.1

Restructuring and other costs which consist principally of non-cash gains and losses on the sale of businesses, product lines and real estate; asset impairment charges; and, in some periods, may also include gains on pension plan curtailment; and gains and losses resulting from changes in estimates for significant litigation-related matters.

No definition available.

Name:	tmo_RestructuringAndRelatedCostsNonCashCosts
Namespace Prefix:	tmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration