Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Sep. 30, 2011	Sep. 27, 2013 Employee	Sep. 28, 2012	Sep. 30, 2011
Commitments And Contingencies [Line Items]
Minimum rentals under operating leases fiscal year 2014		$ 20
Minimum rentals under operating leases fiscal year 2015		17
Minimum rentals under operating leases fiscal year 2016		12.5
Minimum rentals under operating leases fiscal year 2017		9.1
Minimum rentals under operating leases fiscal year 2018		5.9
Operating leases future minimum payments due thereafter		12
Rental expenses		26.0	24.9	23.8
Loan facility to CPTC	165.3	165.3	165.3	165.3
Varian's participation under the CPTC loan facility	115.3	115.3	115.3
Environmental cleanup costs, third-party claim costs, project management costs and legal costs		1.0	1.6	1.3
Receivables of past and future environmental-related expenditures		2.4	2.6
Actual damages found by jury			40
Court ordered amount			102
Enhanced damages			80
Prejudgment interest to the damages award			13
Attorneys' fee added to the judgment			9
Aggregate accrual for ongoing proceedings		5.0
Range of reasonably possible loss for the University of Pittsburg matter, Minimum		0
Range of reasonably possible loss, maximum		102
Number of employees accepted the voluntary retirement program		85
Restructuring charges		6.7		0
Payments for restructuring charges		6.7
Long term accrued product warranty costs		14.1
Royalties
Commitments And Contingencies [Line Items]
Royalty rate maximum		5
Cercla Sites and One Past Facility
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs, minimum		1.9
Estimated environmental remediation costs, maximum		9.8
Amount accrued for environmental remediation expense		1.9
Cercla Sites and One Past Facility | Minimum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies, years		1
Cercla Sites and One Past Facility | Maximum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies, years		30
Other Sites
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs, minimum		6.4
Estimated environmental remediation costs, maximum		36.0
Amount accrued for environmental remediation expense		9.4
Estimated environmental remediation costs, best estimate, undiscounted		$ 12.4
Discount rate for environmental remediation costs, net of inflation		4.00%
Other Sites | Minimum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies, years		1
Other Sites | Maximum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies, years		30