Discontinued Operations - Balance Sheet Disclosures (Details) - USD ($) $ in Millions	Sep. 28, 2018	Sep. 29, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets of discontinued operations	$ 2.3	$ 11.1
Current liabilities of discontinued operations	0.0	2.5
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]
Accounts receivable, net	0.0	8.1
Inventories	0.0	2.9
Prepaid expenses and other current assets	2.3	0.1
Current assets of discontinued operations	2.3	11.1
Total assets of discontinued operations	2.3	11.1
Accounts payable	0.0	2.0
Accrued liabilities	0.0	0.5
Current liabilities of discontinued operations	0.0	2.5
Total liabilities of discontinued operations	$ 0.0	$ 2.5