Discontinued Operations (Details) - USD ($) $ in Millions			12 Months Ended
	Jan. 28, 2017	Jan. 25, 2017	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash received from Varex term facility			$ 0.0	$ 200.0	$ 0.0
Contribution of cash and cash equivalents	$ 81.3		0.0	42.6	$ 0.0
Distribution of Varex				334.1
Varex Imaging | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash received from Varex term facility			200.0
Net assets			2.3
Varex Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Due from				38.7
Minimum | Varex Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services agreement	60 days
Maximum | Varex Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services agreement	24 months
Retained Earnings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Distribution of Varex				$ 334.1
Retained Earnings | Varex Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Distribution of Varex			334.1
Varex Term Facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from term facility		$ 203.0
Transfer of debt outstanding			$ 203.0