Discontinued Operations - Income Statement Disclosures (Details) - USD ($) $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Jul. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net earnings (loss) from discontinued operations	$ 0.0	$ 0.0	$ (13.3)	$ 6.5	$ 23.5	$ 17.0	$ 19.8	$ 17.1		$ (6.8)	$ 77.4	$ 100.6
Less: Net earnings from discontinued operations attributable to noncontrolling interests										0.1	0.5	0.7
Net earnings (loss) from discontinued operations attributable to Varian										(6.9)	76.9	99.9
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues										194.0	596.7	608.4
Cost of revenues										117.3	348.3	357.9
Gross margin										76.7	248.4	250.5
Operating expenses										76.1	132.6	97.2
Operating earnings										0.6	115.8	153.3
Taxes on earnings										7.4	38.4	52.7
Net earnings (loss) from discontinued operations										(6.8)	77.4	100.6
Less: Net earnings from discontinued operations attributable to noncontrolling interests										0.1	0.5	0.7
Net earnings (loss) from discontinued operations attributable to Varian										(6.9)	76.9	$ 99.9
Separation costs									$ 5.4	$ 34.2	$ 16.9