Stockholders' Equity And Stock-Based Compensation (Narrative) (Details) - USD ($)					12 Months Ended				37 Months Ended	41 Months Ended
	Jul. 25, 2016	Apr. 25, 2016	Jan. 25, 2016	Dec. 15, 2015	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014	Sep. 28, 2012	Oct. 31, 2010	Mar. 28, 2014	Oct. 31, 2014	Feb. 29, 2012	Jul. 31, 2011	Jul. 31, 2010	Nov. 30, 2009
Stockholders' Equity And Stock-Based Compensation [Line Items]
Estimated forfeiture rate, percent					10.49%	9.98%	6.13%
Options granted under the plan					2,220,000
Options outstanding to purchase						8,835,000
Recognized tax benefit from the exercise of ISO and ESPP					$ 550,000	$ 328,000	$ 538,000
Percentage of vesting per year									50.00%
Share based compensation expense					66,985,000	67,069,000	65,680,000
Fair value of restricted stock units vested					$ 40,283,000	45,175,000	40,810,000
Year end stock price					$ 54.29
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period					1,407,000
Employee stock options expected to be recognized over a weighted-average period					7 years
Allocated Share-based Compensation Expense					$ 66,985,000	$ 67,069,000	$ 65,680,000
Stock authorized for repurchase					1,100,000,000										$ 250,000,000
Remaining authorization to purchase additional shares					$ 51,900,000
Common stock, dividends declared (in dollars per share)	$ 0.12	$ 0.12	$ 0.12		$ 0.50	$ 0.42	$ 0.00
Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)					500,000,000	500,000,000
Common stock, shares issued (shares)					57,018,362	50,291,426
Class B Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)					500,000,000	500,000,000
Common stock, shares issued (shares)					44,403,847	50,743,311
2005 Stock Plan. [Member] | Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares authorized under plan					38,000,000
Options outstanding to purchase					8,690,000
Weighted Average Remaining Contractual Life, Options outstanding					7 years 1 month 24 days
Options vested and exercisable					4,638,000
Awards Granted Under 2005 Stock Plan Prior To February 2011 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Terms for issuance of stock					2
Awards Granted Under 2005 Stock Plan From February 2011 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Terms for issuance of stock					1.6
Employee Stock Purchase Plan [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage of compensation withheld by employees to purchase common stock					10.00%
Common stock purchase price determined over percentage of closing price					15.00%
Employee Stock Purchase Plan [Member] | Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Maximum value of common stock available for eligible employees					$ 25,000
Maximum number of common stock available for eligible employees					1,000
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Period					6 months
Share-based Compensation Arrangement by Share-based Payment Award, Look Back Commencement Period					1 year
Additional Stock Approved [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock authorized for repurchase											$ 200,000,000	$ 100,000,000	$ 250,000,000	$ 300,000,000
Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest					$ 32,300,000
Employee stock options expected to be recognized over a weighted-average period					2 years 2 months 12 days
Employee Stock Option [Member] | Options Granted Prior To June 2008 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options expiration period					10 years
Employee Stock Option [Member] | Options Granted From June 2008 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period					4 years			36 months
Percentage of stock option becoming exercisable subjected to date of grant					25.00%
Options maximum vesting period, months					4 years			36 months
Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options granted under the plan				419,623
Options outstanding to purchase					397,748
Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share based compensation expense					$ 42,201,000	$ 40,332,000	$ 42,221,000
Stock options expected to vest					$ 70,800,000
Employee stock options expected to be recognized over a weighted-average period					2 years 6 months
Employee and Officer [Member] | Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period					4 years
Options maximum vesting period, months					4 years
Awards Granted Prior to November 2010 [Member] | Director [Member] | Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period									3 years	1 year
Options maximum vesting period, months									3 years	1 year
Awards Granted After November 2010 [Member] | Director [Member] | Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period									2 years
Options maximum vesting period, months									2 years
Minimum [Member] | Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Award vesting percentage					0.00%
Maximum [Member] | Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Award vesting percentage					125.00%