Stockholders' Equity And Stock-Based Compensation (Narrative) (Details) - USD ($)			3 Months Ended		6 Months Ended		37 Months Ended	41 Months Ended
	Apr. 26, 2017	Jan. 25, 2017	Mar. 31, 2017	Apr. 01, 2016	Mar. 31, 2017	Apr. 01, 2016	Oct. 31, 2010	Mar. 28, 2014	Sep. 30, 2016	Oct. 31, 2014	Feb. 29, 2012	Jul. 31, 2011	Jul. 31, 2010	Nov. 30, 2009
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options outstanding to purchase									8,690,000
Year end stock price					$ 52.41
Percentage of vesting per year							50.00%
Common stock, dividends declared (in dollars per share)		$ 0.14	$ 0.14	$ 0.12	$ 0.28	$ 0.24
Remaining authorization to purchase additional shares			$ 201,900,000		$ 201,900,000
Authorization Amount			1,300,000,000		1,300,000,000									$ 250,000,000
Subsequent Event [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, dividends declared (in dollars per share)	$ 0.14
Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest			$ 39,000,000		$ 39,000,000
Employee stock options expected to be recognized over a weighted-average period					2 years 6 months
Performance-Based Stock Options [Member] | Executive Officer [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures					276,199	419,623
Performance-Based Stock Options [Member] | Executive Officer [Member] | Awarded Fiscal 2016 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options outstanding to purchase			397,748		397,748
Performance-Based Stock Options [Member] | Executive Officer [Member] | Awarded Fiscal 2017 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options outstanding to purchase			276,199		276,199
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest			$ 90,500,000		$ 90,500,000
Employee stock options expected to be recognized over a weighted-average period					2 years 9 months 18 days
Restricted Stock Units (RSUs) [Member] | Employees and Officers [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					4 years
Restricted Stock Units (RSUs) [Member] | Awards Granted Prior to November 2010 [Member] | Directors [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							3 years	1 year
Restricted Stock Units (RSUs) [Member] | Awards Granted After November 2010 [Member] | Directors [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							2 years
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%
Additional Stock Approved [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Authorization Amount		$ 200,000,000								$ 200,000,000	$ 100,000,000	$ 250,000,000	$ 300,000,000
Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)			500,000,000		500,000,000				500,000,000
Common stock, shares issued (shares)			57,702,863		57,702,863				57,018,362
Common stock, shares outstanding (shares)			57,702,863		57,702,863				57,018,362
Class A Common Stock [Member] | 2005 Stock Plan. [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares authorized under plan			46,000,000		46,000,000
Options outstanding to purchase			10,013,000		10,013,000
Weighted average remaining contractual life					7 years 1 month 6 days
Options vested and exercisable			5,195,000		5,195,000
Class A Common Stock [Member] | Employee Stock Purchase Plan [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
Purchase period					6 months
Look back commencement period					1 year
Class B Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)			500,000,000		500,000,000				500,000,000
Common stock, shares issued (shares)			44,073,597		44,073,597				44,403,847
Common stock, shares outstanding (shares)			44,073,597		44,073,597				44,403,847
Options Granted Prior To June 2008 [Member] | Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					4 years
Options expiration period					10 years
Options Granted From June Two Thousand Eight Member | Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					36 months
Percentage of stock option becoming exercisable subjected to date of grant					25.00%