STOCKHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Schedule of Amounts Reclassified Out of Other Comprehensive Earnings (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Apr. 01, 2016	Mar. 31, 2017	Apr. 01, 2016
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Revenues	$ 655.0	$ 615.2	$ 1,266.8	$ 1,231.0
Operating expenses	(185.5)	(155.1)	(435.1)	(319.3)
Net earnings attributable to Varian	56.1	97.0	76.5	186.0
Unrealized loss on defined benefit pension and post-retirement benefit plans
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Cost of revenues & Operating expenses	(1.0)	(0.6)	(1.9)	(1.3)
Unrealized gain on cash flow hedging instruments
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Cost of revenues & Operating expenses				0.1
Unrealized loss on available-for-sale-investments
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Cost of revenues & Operating expenses				(0.6)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Net earnings attributable to Varian	(1.0)	(0.5)	(1.9)	(1.8)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gain on cash flow hedging instruments
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Revenues	0.0	0.1	0.0	0.1
Reclassification out of Accumulated Other Comprehensive Income | Unrealized loss on available-for-sale-investments
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Operating expenses	$ 0.0	$ 0.0	$ 0.0	$ (0.6)