Commitments and Contingencies - Additional Information (Detail) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended						12 Months Ended
	Sep. 30, 2011 USD ($)	Sep. 28, 2012 USD ($)	Sep. 30, 2011 USD ($)	Oct. 01, 2010 USD ($)	Sep. 28, 2012 EUR (€)	May 25, 2012 USD ($)	Apr. 25, 2012 USD ($)	Sep. 28, 2012 CERCLA Sites And One Past Facility USD ($)	Sep. 28, 2012 CERCLA Sites And One Past Facility Minimum Y	Sep. 28, 2012 CERCLA Sites And One Past Facility Maximum Y	Sep. 28, 2012 Other Sites USD ($)	Sep. 28, 2012 Other Sites Minimum Y	Sep. 28, 2012 Other Sites Maximum Y
Commitments and Contingencies [Line Items]
Minimum rentals under operating leases fiscal year 2013		$ 18.4
Minimum rentals under operating leases fiscal year 2014		13.6
Minimum rentals under operating leases fiscal year 2015		10.8
Minimum rentals under operating leases fiscal year 2016		8.6
Minimum rentals under operating leases fiscal year 2017		6.1
Operating leases future minimum payments due thereafter		6.5
Rental expenses		24.9	23.8	23.5
Loan facility to CPTC	165.3
Varian's participation under the CPTC loan facility	115
Guaranteed prepayments to a third party	67
Guaranteed prepayments to a third party in fiscal year 2013		28
Environmental cleanup costs, third-party claim costs, project management costs and legal costs		1.6	1.3	1.3
Estimated environmental remediation costs, minimum								2.0			6.3
Estimated environmental remediation costs, maximum								9.4			35.6
Amount accrued for environmental remediation expense								2.0			9.8
Estimated time frames to resolve contingency related to environmental remediation contingencies, years									1	30		1	30
Estimated environmental remediation costs, best estimate, undiscounted											13.1
Discount rate for environmental remediation costs, net of inflation											4.00%
Receivables of past and future environmental-related expenditures	3.0	2.6	3.0
Loss accrual					0.9
Actual damages found by jury		37
Enhanced damages							74
Prejudgment interest to the damages award							13
Damages from sales information was updated until judgment						3
Double damages from sales information was updated until judgment						6
Attorneys' fee added to the judgment						9
Aggregate accrual for ongoing proceedings		$ 5.7