Income Taxes (Schedule of Components of Income from Continuing Operations Before Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Operating Loss Carryforwards [Line Items]
U.K.	$ (97.4)		$ (165.9)	$ (275.3)	$ (107.5)
Non-U.K.	(201.1)		227.5	508.7	214.8
Income (loss) from continuing operations before income taxes	$ (298.5)	$ 66.5	$ 61.6	$ 233.4	$ 107.3

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

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- Definition

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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