Business Combination, Equity Conversion, Post-Combination Expense

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Defined Contribution Plan, Employer Matching Contribution, Amount

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Performance Shares Award, Performance Period

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Performance Shares, Percentage of Ordinary Shares Awarded

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- Definition

Share-Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Granted in Period, Total Fair Value

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Subparagraph (SAB TOPIC 14.F)

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-Name Staff Accounting Bulletin (SAB)

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-Section F

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- Definition

Amount of deferred tax expense from write-off of the deferred tax asset related to deductible stock options at exercise.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 20

-Section 55

-Paragraph 20

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Percentage employer matches of the employee's percentage contribution matched.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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-Name Accounting Standards Codification

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Share Plans (Narrative) (Details) - USD ($)	12 Months Ended
Share Plans (Narrative) (Details) - USD ($)	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation cost	$ 116,100,000	$ 66,800,000	$ 16,000,000
Tax benefit from share-based compensation cost	41,700,000	24,100,000	$ 5,700,000
Intrinsic value of options vested	89,500,000	34,200,000
Tax benefit from stock options exercised	$ 33,100,000	$ 12,000,000
Performance period	3 years
Share Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years
Unrecognized compensation cost, share options	$ 24,800,000
Weighted-average period to recognize unrecognized compensation cost, share options	2 years 8 months
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Weighted-average period to recognize unrecognized compensation cost, share options	2 years 9 months
Fair value of restricted share units granted in period	$ 28,900,000
Fair value of restricted share units vested in period	21,600,000
Unrecognized compensation cost, restricted share units	$ 30,300,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer matching contribution, percent of match	25.00%	15.00%
ESPP employer match - maximum employee contribution	$ 25,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period to recognize unrecognized compensation cost, share options	1 year 9 months
Unrecognized compensation cost	$ 8,900,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period to recognize unrecognized compensation cost, share options	2 years 6 months
Fair value of restricted share units vested in period	$ 127,400,000
Unrecognized compensation cost	$ 2,300,000
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under 2013 Plan	5,700,000.0
2015 Mallinckrodt Pharmaceuticals Stock and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under 2013 Plan	17,800,000.0
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	12,100,000.0
Questcor Pharmaceuticals, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Post combination expense	$ 90,400,000
Selling, general and administrative \| Questcor Pharmaceuticals, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Post combination expense	80,600,000
Restructuring \| Questcor Pharmaceuticals, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Post combination expense	$ 9,800,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of ordinary shares to be awarded	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of ordinary shares to be awarded	200.00%