Credit Facility - Additional Information (Detail) In Millions, unless otherwise specified	1 Months Ended												9 Months Ended
	Jun. 29, 2012 Two Thousand Twelve Credit Facility USD ($)	Apr. 27, 2012 Two Thousand Twelve Credit Facility USD ($) Year	Apr. 27, 2012 Two Thousand Twelve Credit Facility Minimum	Apr. 27, 2012 Two Thousand Twelve Credit Facility Maximum	Apr. 27, 2012 Two Thousand Twelve Credit Facility Interest Accrued Description One	Apr. 27, 2012 Two Thousand Twelve Credit Facility Interest Accrued Description One Minimum	Apr. 27, 2012 Two Thousand Twelve Credit Facility Interest Accrued Description One Maximum	Apr. 27, 2012 Two Thousand Twelve Credit Facility Interest Accrued Description Two	Apr. 27, 2012 Two Thousand Twelve Credit Facility Interest Accrued Description Two Minimum	Apr. 27, 2012 Two Thousand Twelve Credit Facility Interest Accrued Description Two Maximum	Sep. 30, 2011 Amended Bofa Credit Facility USD ($)	Jun. 29, 2012 Japanese Line Of Credit Facility JPY (¥)	Jun. 29, 2012 Sumitomo Credit Facility USD ($)	Jun. 29, 2012 Sumitomo Credit Facility JPY (¥)
Line of Credit Facility
Credit facility, term		5
Loan facility, maximum borrowing capacity		$ 300									$ 300	¥ 2,700		¥ 3,000
Maximum amount that can be used to support letters of credit		50									25
Maximum amount permitted for swing line loans		25
Loan facility, maximum increase to aggregate commitments		200
Percentage of Varian Medical Systems Nederland Holdings B.V. voting shares pledged	65.00%
Line of credit, interest rate calculation (Eurodollar rate margin)						1.25%	1.50%
Margin added if base rate is based on federal funds rate								0.50%
Line of credit, interest rate calculation					Eurodollar rate (as defined in the credit agreement), plus a margin of 1.25% to 1.5% based on a leverage ratio involving funded indebtedness and earnings before interest, taxes and depreciation and amortization ("EBITDA" )			Based upon a base rate of the highest of (a) the federal funds rate plus 0.5%, (b) BofA's announced prime rate or (c) the Eurodollar rate plus 1%, plus a margin of 0.25% to 0.5% based on the same leverage ratio					Basic loan rate announced by the Bank of Japan plus a margin of 0.5% per annum.	Basic loan rate announced by the Bank of Japan plus a margin of 0.5% per annum.
Margin added if base rate is based on Eurodollar rate								1.00%
Line of credit, interest rate calculation (base rate margin)									0.25%	0.50%
Commitment fees at an annual rate			0.25%	0.30%
Line of credit, commitment fee		0.25% to 0.30% based on the same leverage ratio
Line of credit, amount outstanding	$ 165.0										$ 181.0		$ 3.8	¥ 300.0
Line of credit, interest rate	1.62%										1.05%		0.67%	0.67%
Line of credit facility, maturity date													Feb. 28, 2013	Feb. 28, 2013
Line of credit, interest rate calculation (Bank of Japan basis loan rate margin)													0.50%	0.50%