Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	24.50%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ (71.0)
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	32.0
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit)	231.0
Tax credit carryforward	9.7
Foreign net operating loss carryforwards	290.7
Gross unrecognized tax benefits	224.6	$ 196.9	$ 146.5	$ 150.4
Unrecognized tax benefits affecting the effective tax rate if recognized	157.3
Interest and penalties expense/(benefit) recognized in income tax expense	(0.5)	5.2	$ (3.6)
Accrued interest and penalties	12.8	$ 11.2
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Amount of reasonably possible unrecognized benefit change	79.0
Other long-term liabilities [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit)	$ 237.0