Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Aug. 02, 2020 USD ($) $ / shares	Oct. 02, 2020 USD ($) customer	Oct. 02, 2020 USD ($) customer cancer_center	Oct. 02, 2020 USD ($) specialty_hospital customer	Jul. 03, 2020 USD ($)	Apr. 03, 2020 USD ($)	Nov. 01, 2019 USD ($)	Oct. 31, 2019 USD ($)	Sep. 27, 2019 USD ($)	Sep. 28, 2018 USD ($)	Apr. 02, 1999 company
Significant Accounting Policies [Line Items]
Number of multi-disciplinary cancer centers			13	13
Accessible Liquidity		$ 1,600,000,000	$ 1,600,000,000	$ 1,600,000,000
Cash and cash equivalents		766,100,000	766,100,000	766,100,000					$ 531,400,000
Revolving credit facility, remaining borrowing capacity		845,000,000	845,000,000	845,000,000
Revolving credit facility, maximum borrowing capacity		1,200,000,000	1,200,000,000	1,200,000,000
Number of publicly traded companies | company											3
Number of publicly traded companies distributed to stockholders | company											2
Goodwill		$ 623,900,000	623,900,000	623,900,000					612,200,000	$ 293,600,000
Warranty period		12 months
Capitalized software development costs for software sold to customers		$ 0	0	0
Other
Significant Accounting Policies [Line Items]
Goodwill		$ 169,200,000	$ 169,200,000	$ 169,200,000					$ 164,300,000	$ 0
Interventional Solutions Reporting Unit
Significant Accounting Policies [Line Items]
Goodwill						$ 164,300,000
Fair value in excess of carrying amount					$ 72,000,000
Percentage of fair value in excess of carrying amount					27.00%
Interventional Solutions Reporting Unit | Other
Significant Accounting Policies [Line Items]
Fair value in excess of carrying amount						$ 20,000,000
Percentage of fair value in excess of carrying amount						7.00%
Revolving Credit Facility
Significant Accounting Policies [Line Items]
Revolving credit facility, maximum borrowing capacity							$ 1,200,000,000	$ 1,800,000,000
Merger Agreement With Siemens Healthineers AG
Significant Accounting Policies [Line Items]
Acquisition purchase price	$ 16,400,000,000
Acquisition share price (in AUD per share) | $ / shares	$ 177.50
Potential termination fee	$ 450,000,000.0
Minimum
Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life (in years)		1 year
Manufacturing, commissioning and installation period		18 months
Minimum | Merger Agreement With Siemens Healthineers AG
Significant Accounting Policies [Line Items]
Reverse termination fees	450,000,000.0
Maximum
Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life (in years)		23 years
Manufacturing, commissioning and installation period		24 months
Maximum | Merger Agreement With Siemens Healthineers AG
Significant Accounting Policies [Line Items]
Reverse termination fees	$ 925,000,000.0
Land Improvements
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)		15 years
Building | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)		20 years
Building | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)		30 years
Machinery and Equipment | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)		3 years
Machinery and Equipment | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)		7 years
Accounts Receivable
Significant Accounting Policies [Line Items]
Number of customers representing more than 10% | customer		0	0	0
India
Significant Accounting Policies [Line Items]
Number of specialty hospitals | specialty_hospital				1
Sri Lanka
Significant Accounting Policies [Line Items]
Number of multi-disciplinary cancer centers | specialty_hospital				1