Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Share Amounts (Detail) - shares shares in Thousands	12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 28, 2013
Earnings Per Share [Line Items]
Basic weighted average common shares outstanding (in shares)	280,566	275,499	268,704
Weighted Average Common Stock Equivalents From Assumed Exercise Of Stock Options And Restricted Stock Units	2,898	2,368	0
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	6,073	493	0
Diluted weighted average common shares outstanding (in shares)	289,537	278,360	268,704
Outstanding Stock Options [Member]
Weighted-average anti-dilutive shares related to:
Weighted-average anti-dilutive shares (in shares)	1,502	5,033	8,445
Restricted Stock Units [Member]
Weighted-average anti-dilutive shares related to:
Weighted-average anti-dilutive shares (in shares)	49	20	1,109