STOCKHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Schedule of Amounts Reclassified Out of Other Comprehensive Earnings (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 30, 2016	Jan. 01, 2016
Reclassification Adjustment Out Of Accumulated Comprehensive Income [Line Items]
Operating Expenses	$ (296.1)	$ (193.0)
Net earnings attributable to Varian	20.4	89.0
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	(0.9)	(0.6)
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	(0.9)	(1.2)
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	$ (0.6)