Credit Facilities (Details)	12 Months Ended
	Sep. 30, 2011 USD ($)	Oct. 01, 2010 USD ($)	Oct. 02, 2009 USD ($)	Sep. 30, 2011 Minimum [Member] Interest Accrued Description One [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Minimum [Member] Interest Accrued Description Two [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Minimum [Member] Japanese Line Of Credit Facility [Member]	Sep. 30, 2011 Minimum [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Maximum [Member] Interest Accrued Description One [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Maximum [Member] Interest Accrued Description Two [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Maximum [Member] Japanese Line Of Credit Facility [Member]	Sep. 30, 2011 Maximum [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Interest Accrued Description One [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Interest Accrued Description Two [Member] Amended BofA Credit Facility [Member]	Sep. 30, 2011 Japanese Line Of Credit Facility [Member] USD ($)	Sep. 30, 2011 Japanese Line Of Credit Facility [Member] JPY (¥)	Sep. 30, 2011 Amended BofA Credit Facility [Member] USD ($)	Oct. 01, 2010 Amended BofA Credit Facility [Member] USD ($)	Sep. 30, 2011 Japanese Overdraft Facility [Member]	Mar. 31, 2011 Japanese Overdraft Facility [Member] JPY (¥)
Line of Credit Facility [Line Items]
Credit facility, maximum amount outstanding															¥ 2,700,000,000	$ 300,000,000			¥ 500,000,000
Percentage of Varian Medical Systems Nederland B.V. voting shares pledged																65.00%
Amount deemed committed if Japanese Line of Credit were used																35,000,000
Maximum credit available if Japanese Line of Credit were used																265,000,000
Line of Credit, interest rate calculation												London Interbank Offered Rate ("LIBOR") plus a margin of 0.75% to 1.25% based on a leverage ratio	funds rate plus 0.5% or BofA's announced prime rate, whichever is greater, minus a margin of 0.5% to 0% based on a leverage ratio	basic loan rate announced by the Bank of Japan plus a margin of 1.25% to 1.50% based on a leverage ratio	basic loan rate announced by the Bank of Japan plus a margin of 1.25% to 1.50% based on a leverage ratio
Line of Credit, commitment fee																0.2% to 0.3% based on a leverage ratio
Line of Credit, interest rate calculation (LIBOR rate margin)				0.75%				1.25%
Line of Credit, interest rate calculation (Base rate margin)					0.50%				0.00%
Line of Credit, amount outstanding														0		181,000,000	20,000,000
Line of Credit facility, maturity date	June 30, 2012																	June 30, 2011
Line of Credit, interest rate																1.05%	1.51%
Margin added if base rate is based on federal funds rate													0.50%
Amount used to support letters of credit, outstanding																0	0
Maximum amount that can be used to support letters of credit																25,000,000
Commitment fees at an annual rate							0.20%				0.30%
Line of Credit, interest rate calculation (Bank of Japan basis loan rate margin)						1.25%				1.50%
Accrued interest on overdraft facility																		0.81%
Line of Credit, commitment fees amount	332,000,000	231,000,000	256,000,000
Line of Credit, interest paid	$ 800,000	$ 300,000	$ 200,000