DISCONTINUED OPERATIONS - Income Statement Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from discontinued operations	$ 0.0	$ 0.0	$ 0.0	$ (6.8)
Less: Net earnings from discontinued operations attributable to noncontrolling interests	0.0	0.0	0.0	0.1
Net loss from discontinued operations attributable to Varian	$ 0.0	$ 0.0	$ 0.0	(6.9)
Separation costs				34.2
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
Cost of revenues				117.3
Gross margin				76.7
Operating expenses				76.1
Operating earnings				0.6
Taxes on earnings				7.4
Net loss from discontinued operations				(6.8)
Less: Net earnings from discontinued operations attributable to noncontrolling interests				0.1
Net loss from discontinued operations attributable to Varian				$ (6.9)