DISCONTINUED OPERATIONS - Income Statement Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 30, 2018	Mar. 31, 2017	Mar. 30, 2018	Mar. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from discontinued operations	$ 0.0	$ (13.3)	$ 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	(13.3)	$ 0.0	(6.9)
Separation costs		19.3		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		42.5		194.0
Cost of revenues		24.6		117.3
Gross margin		17.9		76.7
Operating expenses		29.7		76.1
Operating earnings		(11.8)		0.6
Taxes on earnings		1.5		7.4
Net loss from discontinued operations		(13.3)		(6.8)
Less: Net earnings from discontinued operations attributable to noncontrolling interests		0.0		0.1
Net loss from discontinued operations attributable to Varian		$ (13.3)		$ (6.9)