Stockholders' Equity And Stock-Based Compensation (Summary Of Stock Options Issued To Officers, Directors, And Employees Under 2000 Stock Incentive Plan And 2005 Stock Plan) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 15, 2016	Sep. 27, 2019	Sep. 28, 2012	Dec. 15, 2015
Shares
Options outstanding at September 28, 2018		7,365,000
Grants		1,253,000
Exercises		(1,177,000)
Forfeitures and cancellations		(240,000)
Options vested and expected to vest at September 27, 2019		6,921,000
Weighted-Average Exercise Price
Options outstanding at September 28, 2018		$ 43.51
Grants		64.61
Exercises		36.17
Forfeitures and cancellations		54.24
Options outstanding at September 27, 2019		48.03
Options vested and expected to vest at September 27, 2019		47.43
Options exercisable at September 27, 2019		$ 41.18
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life, Options vested and expected to vest at September 28, 2012		6 years 2 months 12 days
Weighted Average Remaining Contractual Life, Options exercisable		5 years 4 months 24 days
Aggregate Intrinsic Value, Options outstanding		$ 114,500
Aggregate Intrinsic Value, Options vested and expected to vest		114,091
Aggregate Intrinsic Value, Options exercisable		$ 98,496
Year End Stock Price		$ 63.79
Two Thousand Five Stock Plan Member | Common Class A [Member]
Shares
Options outstanding at September 27, 2019		7,201,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life, Options outstanding		6 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number		4,355,000
Awards Granted Under 2005 Stock Plan Prior To February 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms for issuance of stock		2
Awards Granted Under 2005 Stock Plan From February 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms for issuance of stock		1.6
Employee Stock Option [Member] | Options Granted From June 2008 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options maximum vesting period, months			36 months
Share Based Compensation Arrangement By Share Based Payment Award Options Becoming Exercisable		25.00%
Performance-Based Stock Options [Member] | Awarded Fiscal 2017 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	276,199
Shares
Options outstanding at September 27, 2019		758,299
Performance-Based Stock Options [Member] | Awarded Fiscal 2016 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number				334,623