Equity Stock Repurchase Program (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014	Mar. 16, 2016	Nov. 19, 2015	Jan. 23, 2015
Class of Stock [Line Items]
Repurchase of ordinary shares, value	$ 652.9	$ 92.2	$ 17.5
March 2016 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 350.0
Repurchase of ordinary shares, shares	0	0
Repurchase of ordinary shares, value	$ 0.0	$ 0.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 350.0
November 2015 Share Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 500.0
Repurchase of ordinary shares, shares	6,510,824	0
Repurchase of ordinary shares, value	$ 425.6	$ 0.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 74.4
January 2015 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 300.0
Repurchase of ordinary shares, shares	3,199,279	823,592
Repurchase of ordinary shares, value	$ 225.0	$ 75.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 0.0