Segment and Geographical Data (Schedule of Net Sales and Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Millions		3 Months Ended									12 Months Ended
		Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales		$ 792.3	$ 793.9	$ 824.5	$ 810.9	$ 829.9	$ 887.2	$ 866.6	$ 815.8	$ 811.2	$ 3,221.6	$ 3,380.8	$ 2,923.1
Long-Lived Assets		979.0				893.5					979.0
United States
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales	[1]					763.7					2,899.0	3,095.4	2,647.0
Long-Lived Assets	[2]	788.5				759.1					788.5
EMEA
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales	[1]					52.8					242.3	211.8	159.0
Long-Lived Assets	[2],[3]	127.0				82.9					127.0
EMEA | IRELAND
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Long-Lived Assets		126.0				80.9					126.0
Other Countries
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales	[1]					13.4					80.3	$ 73.6	$ 117.1
Long-Lived Assets	[2]	$ 63.5				$ 51.5					$ 63.5

[1] Net sales are attributed to regions based on the location of the entity that records the transaction, none of which relate to the country of Ireland.

[2] Long-lived assets are primarily composed of property, plant and equipment, net.

[3] Includes long-lived assets located in Ireland of $126.0 million and $80.9 million