STOCKHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Schedule of Amounts Reclassified Out of Other Comprehensive Earnings (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Revenues	$ 662.4	$ 642.9	$ 1,929.2	$ 1,873.9
Operating expenses	(177.0)	(181.4)	(612.1)	(500.7)
Net earnings attributable to Varian	90.4	98.8	166.9	284.8
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	(0.9)	(0.6)	(2.8)	(1.9)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Net earnings attributable to Varian	(0.9)	(1.3)	(2.8)	(3.1)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized loss on cash flow hedging instruments
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Revenues	0.0	(0.7)	0.0	(0.6)
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)