Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Apr. 02, 2011
Discontinued Operations [Abstract]
Discontinued Operation Gain (Loss) on Disposal, Net of Tax	$ 0.3	$ (0.5)

Gain (loss), after tax expense (benefit), resulting from the sale of a business component included in discontinued operations, includes gain (loss), after tax, recognized at the date of sale, provision recognizing a loss, after tax benefit, for initial, or subsequent, write-down to fair value (less cost to sell) of a disposal group, which remains unsold as of the reporting date, and adjustments, after tax, to an amount previously reported in discontinued operations that is directly related to the disposal in a prior period.

No definition available.

Name:	tmo_DiscontinuedOperationGainLossOnDisposalNetOfTax
Namespace Prefix:	tmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration