DISCONTINUED OPERATIONS - Income Statement Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Apr. 01, 2016	Mar. 31, 2017	Apr. 01, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net (loss) earnings from discontinued operations	$ (13.3)	$ 19.8	$ (6.8)	$ 36.9
Less: Net earnings from discontinued operations attributable to noncontrolling interests	0.0	0.1	0.1	0.0
Net (loss) earnings from discontinued operations attributable to Varian	(13.3)	19.7	(6.9)	36.9
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	42.5	143.6	194.0	284.9
Cost of revenues	24.6	84.5	117.3	168.6
Gross margin	17.9	59.1	76.7	116.3
Operating expenses	29.7	28.1	76.1	57.0
Operating (loss) earnings	(11.8)	31.0	0.6	59.3
Taxes on earnings	1.5	11.2	7.4	22.4
Net (loss) earnings from discontinued operations	(13.3)	19.8	(6.8)	36.9
Less: Net earnings from discontinued operations attributable to noncontrolling interests	0.0	0.1	0.1	0.0
Net (loss) earnings from discontinued operations attributable to Varian	(13.3)	$ 19.7	(6.9)	$ 36.9
Separation costs	$ 19.3		$ 34.2