Income Taxes (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Jan. 01, 2018	Jun. 29, 2018	Dec. 29, 2017	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Sep. 29, 2017
Income Tax Contingency [Line Items]
Federal tax rate	21.00%	24.60%	35.00%			24.60%
Provision for income taxes		$ 13,302		$ 20,117	$ 198,332	$ 49,666
Unrecognized tax benefits, gross		105,100			105,100		$ 98,700
Unrecognized tax benefits if recognized, would affect our effective tax rate		$ 92,200			$ 92,200		$ 85,000
Effective tax rate (as a percent)		13.80%		20.90%	73.20%	21.60%
Impact Of Tax Cuts And Jobs Act [Member]
Income Tax Contingency [Line Items]
Provision for income taxes			$ 154,600
Decrease in deferred tax assets			57,900
Impact Of Tax Cuts And Jobs Act, Repatriation Transition Tax [Member]
Income Tax Contingency [Line Items]
Tax liability			$ 96,700