Condensed Consolidated Statements of Stockholder's Equity Statement - USD ($) shares in Thousands, $ in Thousands		Total	Common Stock and Additional Paid in Capital	Treasury Stock	Accumulated Other Comprehensive Income	Accumulated Deficit	Number of Common Shares [Member]
Balance at Sep. 30, 2017			$ 6,185,088	$ (633,740)	$ 76,794	$ (3,980,458)
Common Stock, Shares, Issued at Sep. 30, 2017							101,672
Treasury Stock, Shares at Sep. 30, 2017				(30,008)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under stock plans, shares							1,351
Issuances under stock plans, Value			3,889
Stock-based compensation expense			28,580
Adjustments to Additional Paid in Capital, Other			0
Repurchases of Treasury Stock, shares				(5,093)
Repurchases of Treasury Stock, Value				$ 150,162
Other comprehensive income (loss)		$ (189)			(189)
Cumulative effect of new accounting pronouncement	[1]					43,269
Net income (loss)		(96,315)				(96,315)
Common Stock, Shares, Issued at Jun. 30, 2018							103,023
Treasury Stock, Shares at Jun. 30, 2018				(35,101)
Balance at Jun. 30, 2018		1,476,756	6,217,557	$ (783,902)	76,605	(4,033,504)
Balance at Mar. 31, 2018			6,207,471	$ (754,279)	77,265	(4,067,467)
Common Stock, Shares, Issued at Mar. 31, 2018							102,700
Treasury Stock, Shares at Mar. 31, 2018				(34,115)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under stock plans, shares							323
Issuances under stock plans, Value			450
Stock-based compensation expense			9,636
Adjustments to Additional Paid in Capital, Other			0
Repurchases of Treasury Stock, shares				(986)
Repurchases of Treasury Stock, Value				$ 29,623
Other comprehensive income (loss)		(660)			(660)
Cumulative effect of new accounting pronouncement						0
Net income (loss)		33,963				33,963
Common Stock, Shares, Issued at Jun. 30, 2018							103,023
Treasury Stock, Shares at Jun. 30, 2018				(35,101)
Balance at Jun. 30, 2018		1,476,756	6,217,557	$ (783,902)	76,605	(4,033,504)
Balance at Sep. 29, 2018		1,472,844	6,222,988	$ (791,366)	73,944	(4,032,722)
Common Stock, Shares, Issued at Sep. 29, 2018							103,128
Treasury Stock, Shares at Sep. 29, 2018				(35,351)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under stock plans, shares							2,281
Issuances under stock plans, Value			12,719
Stock-based compensation expense			20,578
Adjustments to Additional Paid in Capital, Other			138
Repurchases of Treasury Stock, shares				(480)
Repurchases of Treasury Stock, Value				$ 12,752
Other comprehensive income (loss)		(15,943)			(15,943)
Cumulative effect of new accounting pronouncement	[2]					28,130
Net income (loss)		121,758				121,758
Common Stock, Shares, Issued at Jun. 29, 2019							105,409
Treasury Stock, Shares at Jun. 29, 2019				(35,831)
Balance at Jun. 29, 2019		1,627,472	6,256,423	$ (804,118)	58,001	(3,882,834)
Balance at Mar. 30, 2019			6,244,907	$ (803,514)	65,081	(3,925,755)
Common Stock, Shares, Issued at Mar. 30, 2019							104,796
Treasury Stock, Shares at Mar. 30, 2019				(35,806)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under stock plans, shares							613
Issuances under stock plans, Value			3,380
Stock-based compensation expense			8,136
Adjustments to Additional Paid in Capital, Other			0
Repurchases of Treasury Stock, shares				(25)
Repurchases of Treasury Stock, Value				$ 604
Other comprehensive income (loss)		(7,080)			(7,080)
Cumulative effect of new accounting pronouncement						0
Net income (loss)		42,921				42,921
Common Stock, Shares, Issued at Jun. 29, 2019							105,409
Treasury Stock, Shares at Jun. 29, 2019				(35,831)
Balance at Jun. 29, 2019		$ 1,627,472	$ 6,256,423	$ (804,118)	$ 58,001	$ (3,882,834)

[1] Due to the adoption of ASU 2016-09 "Improvements to Employee Share-Based Payment Accounting (Topic 718)".

[2] Due to the adoption of ASU 2014-09 "Revenue from Contracts with Customers (Topic 606)" using the modified retrospective approach.