Line Of Credit Facility, Future Contingent Maximum Borrowing Capacity

No definition available.

Name:	mnk_LineOfCreditFacilityFutureContingentMaximumBorrowingCapacity
Namespace Prefix:	mnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Long-term Loans Payable, Periodic Amortization Payment, Percentage of Original Principal Amount

+ References

No definition available.

+ Details

Name:	mnk_LongtermLoansPayablePeriodicAmortizationPaymentPercentageofOriginalPrincipalAmount
Namespace Prefix:	mnk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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.

+ References

No definition available.

+ Details

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

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

+ Details

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

- Definition

Percentage of fee on unused borrowings under debtor-in-possession financing arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtorInPossessionFinancingFeeOnUnusedBorrowings
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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

- Definition

Weighted average interest rate of long-term debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=mnk_ReceivablesecuritizationMaturityDateofJuly2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mnk_ReceivableSecuritizationMaturityDateofJuly2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mnk_TermLoanandNewTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mnk_A2015RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mnk_A2017RevolvingCreditFacilityMemberDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
Debt (Narrative) (Details) - USD ($) $ in Millions	Jul. 28, 2017	Sep. 29, 2017	Sep. 29, 2017	Feb. 28, 2017	Dec. 30, 2016
Debt Instrument
Long-term Debt		$ 5,592.5	$ 5,592.5		$ 5,965.8
Total Debt		5,911.3	5,911.3		6,237.6
Receivable securitization, Maturity Date of July 2020 [Member]
Debt Instrument
Long-term Debt		$ 200.0	$ 200.0		0.0
Secured Debt \| Receivable securitization, Maturity Date of July 2020 [Member]
Debt Instrument
Line Of Credit Facility, Future Contingent Maximum Borrowing Capacity	$ 300.0
Debt Instrument, Basis Spread on Variable Rate	0.90%
Line of Credit Facility, Commitment Fee Percentage	0.40%
Line of Credit Facility, Maximum Borrowing Capacity	$ 250.0
Secured Debt \| Receivable Securitization
Debt Instrument
Interest rate		2.13%	2.13%
Long-term Line of Credit		$ 200.0	$ 200.0
Secured Debt \| Term Loan and New Term Loan
Debt Instrument
Long-term Debt				$ 1,865.0
Debt Instrument, Basis Spread on Variable Rate		2.75%
Long-term Loans Payable, Periodic Amortization Payment, Percentage of Original Principal Amount		0.25%
Repayments of Debt			83.5
Write off of Deferred Debt Issuance Cost			$ 10.0
Long-term Debt, Weighted Average Interest Rate		4.08%	4.08%
Total Debt		$ 1,855.7	$ 1,855.7
Secured Debt \| 2015 Revolving Credit Facility
Debt Instrument
Long-term Debt					100.0
Secured Debt \| 2017 Revolving Credit Facility [Member] [Domain]
Debt Instrument
Long-term Debt		$ 0.0	$ 0.0
Revolving Credit Facility
Debt Instrument
Interest rate		3.58%	3.58%
Long-term Line of Credit		$ 0.0	$ 0.0
Unsecured Debt \| 2015 Revolving Credit Facility
Debt Instrument
Line of Credit Facility, Maximum Borrowing Capacity					500.0
Unsecured Debt \| 2017 Revolving Credit Facility [Member] [Domain]
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate		2.25%
Line of Credit Facility, Maximum Borrowing Capacity		$ 900.0	$ 900.0
Debtor-in-Possession Financing, Fee on Unused Borrowings		0.275%	0.275%
Letter of Credit [Member] \| 2015 Revolving Credit Facility
Debt Instrument
Line of Credit Facility, Maximum Borrowing Capacity					$ 150.0
Letter of Credit [Member] \| 2017 Revolving Credit Facility [Member] [Domain]
Debt Instrument
Line of Credit Facility, Maximum Borrowing Capacity		$ 50.0	$ 50.0