Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 29, 2017	Sep. 30, 2016
Deferred tax assets:
Inventory	$ 7.4	$ 8.1
Bad debts	0.1	0.2
Accrued compensation and benefits	7.1	5.4
Product returns, allowances and warranty	5.2	8.6
Restructuring	0.1	0.8
Intangible assets	10.6	11.6
Share-based and other deferred compensation	40.2	40.2
Net operating loss carry forwards	7.7	7.4
Federal tax credits	20.1	14.7
State tax credits	71.0	64.0
Deferred Tax Assets, Property, Plant and Equipment	7.9	0.0
Other - net	2.7	5.6
Deferred tax assets	180.1	166.6
Less valuation allowance	(90.9)	(79.1)
Net deferred tax assets	89.2	87.5
Deferred tax liabilities:
Prepaid insurance	(0.9)	(0.8)
Property, plant and equipment	(24.8)	(16.5)
Intangible assets	(6.2)	(8.4)
Deferred Tax Liabilities, Net	31.9	25.7
Total deferred tax assets	$ 57.3	$ 61.8