Restructuring and Related Charges (Schedule of Restructuring Reserves by Type of Cost) (Details) $ in Millions	3 Months Ended
Dec. 30, 2016 USD ($)
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 18.5
Charges	3.8
Cash payments	(7.5)
Ending Balance	14.8
Restructuring Fiscal 2016 Plan [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	6.2
Charges	3.7
Cash payments	(0.4)
Ending Balance	9.5
2013 Mallinckrodt program
Restructuring Reserve [Roll Forward]
Beginning Balance	11.8
Charges	0.0
Cash payments	(6.7)
Ending Balance	5.1
Acquisitions
Restructuring Reserve [Roll Forward]
Beginning Balance	0.5
Charges	0.1
Cash payments	(0.4)
Ending Balance	$ 0.2

Cash Restructuring Charges

No definition available.

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Namespace Prefix:	mnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RestructuringPlanAxis=mnk_RestructuringFiscal2016PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=mnk_RestructuringFiscal2013PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=mnk_BusinessAcquisitionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: