CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Total Varian Stockholders' Equity	Noncontrolling Interests
Beginning Balance (in shares) at Sep. 30, 2016		93.7
Balance at beginning of period at Sep. 30, 2016	$ 1,797.9	$ 93.7	$ 678.6	$ 1,122.7	$ (100.8)	$ 1,794.2	$ 3.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings, excluding prior business	219.1			218.5		218.5	0.6
Other comprehensive earnings (loss)	32.0				32.0	32.0
Issuance of common stock (in shares)		1.4
Issuance of common stock	70.7	$ 1.4	69.3			70.7
Shares repurchased for tax withholdings on vesting of restricted stock and restricted stock units (in shares)		(0.1)
Tax withholdings on vesting of equity awards	(10.7)	$ (0.1)	(10.6)			(10.7)
Share-based compensation expense	$ 40.8		40.8			40.8
Repurchases of common stock (in shares)	(3.3)	(3.3)
Repurchases of common stock	$ (294.5)	$ (3.3)	(62.7)	(228.5)		(294.5)
Distribution of Varex	(334.1)			(334.1)		(334.1)
Other	0.7		0.7			0.7
Ending Balance (in shares) at Sep. 29, 2017		91.7
Balance at end of period at Sep. 29, 2017	1,521.9	$ 91.7	716.1	778.6	(68.8)	1,517.6	4.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings, excluding redeemable noncontrolling interest	150.3			149.9		149.9	0.4
Other comprehensive earnings (loss)	3.5				3.5	3.5
Issuance of common stock (in shares)		1.2
Issuance of common stock	60.7	$ 1.2	59.5			60.7
Shares repurchased for tax withholdings on vesting of restricted stock and restricted stock units (in shares)		(0.1)
Tax withholdings on vesting of equity awards	(11.6)	$ (0.1)	(11.5)			(11.6)
Share-based compensation expense	$ 45.9		45.9			45.9
Repurchases of common stock (in shares)	(1.6)	(1.6)
Repurchases of common stock	$ (181.9)	$ (1.6)	(32.5)	(147.8)		(181.9)
Other	$ (0.1)		0.6	(0.3)		0.3	(0.4)
Ending Balance (in shares) at Sep. 28, 2018	91.2	91.2
Balance at end of period at Sep. 28, 2018	$ 1,588.7	$ 91.2	778.1	780.4	(65.3)	1,584.4	4.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings, excluding redeemable noncontrolling interest	292.2			291.9		291.9	0.3
Other comprehensive earnings (loss)	(36.8)				(36.8)	(36.8)
Issuance of common stock (in shares)		1.1
Issuance of common stock	63.4	$ 1.1	62.3			63.4
Shares repurchased for tax withholdings on vesting of restricted stock and restricted stock units (in shares)		(0.1)
Tax withholdings on vesting of equity awards	(14.5)	$ (0.1)	(14.4)			(14.5)
Share-based compensation expense	$ 47.8		47.8			47.8
Repurchases of common stock (in shares)	(1.4)	(1.4)
Repurchases of common stock	$ (166.7)	$ (1.4)	(28.2)	(137.1)		(166.7)
Acquisition of Cancer Treatment Services International	5.0						5.0
Other	$ (1.5)			(1.2)		(1.2)	(0.3)
Ending Balance (in shares) at Sep. 27, 2019	90.8	90.8
Balance at end of period at Sep. 27, 2019	$ 1,777.6	$ 90.8	$ 845.6	$ 934.0	$ (102.1)	$ 1,768.3	$ 9.3