Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 26, 2014	Dec. 27, 2013
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities	$ 216.8	$ 22.1
Cash Flows From Investing Activities:
Capital expenditures	(22.3)	(21.7)
Intercompany loan investment	0mnk_IntercompanyLoanInvestment	0mnk_IntercompanyLoanInvestment
Investment in subsidiary	0
Restricted cash	0.4	4.1
Other	1.0	5.0
Net cash used in investing activities	(20.9)	(12.6)
Cash Flows From Financing Activities:
Repayment of external debt and capital leases	(7.8)	(0.3)
Excess tax benefit from share-based compensation	8.9	1.3
Proceeds from exercise of share options	8.7	4.2
Repurchase of shares	(10.6)	(0.9)
Intercompany loan borrowings, net	0mnk_ProceedsFromIntercompanyBorrowings	0mnk_ProceedsFromIntercompanyBorrowings
Capital contribution	0us-gaap_ProceedsFromContributedCapital
Other	0	(0.1)
Net cash (used in) provided by financing activities	(0.8)	4.2
Effect of currency rate changes on cash	(3.9)	(1.4)
Net increase in cash and cash equivalents	191.2	12.3
Cash and cash equivalents at beginning of period	707.8	275.5
Cash and cash equivalents at end of period	899.0	287.8
Mallinckrodt plc
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities	14.7	(5.0)
Cash Flows From Investing Activities:
Capital expenditures	0	0
Intercompany loan investment	(11.9)	0
Investment in subsidiary	0
Restricted cash	0	0
Other	0	0
Net cash used in investing activities	(11.9)	0
Cash Flows From Financing Activities:
Repayment of external debt and capital leases	0	0
Excess tax benefit from share-based compensation	0	0
Proceeds from exercise of share options	8.7	4.2
Repurchase of shares	(10.6)	(0.9)
Intercompany loan borrowings, net	0	1.5
Capital contribution	0
Other		0.1
Net cash (used in) provided by financing activities	(1.9)	4.9
Effect of currency rate changes on cash	0	0
Net increase in cash and cash equivalents	0.9	(0.1)
Cash and cash equivalents at beginning of period	0.3	1.2
Cash and cash equivalents at end of period	1.2	1.1
Mallinckrodt International Finance S.A.
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities	(38.3)	(20.0)
Cash Flows From Investing Activities:
Capital expenditures	0	0
Intercompany loan investment	0	(1.5)
Investment in subsidiary	(20.0)
Restricted cash	0	0
Other	0	0
Net cash used in investing activities	(20.0)	(1.5)
Cash Flows From Financing Activities:
Repayment of external debt and capital leases	(3.3)	0
Excess tax benefit from share-based compensation	0	0
Proceeds from exercise of share options	0	0
Repurchase of shares	0	0
Intercompany loan borrowings, net	182.5	(0.1)
Capital contribution	0
Other		0
Net cash (used in) provided by financing activities	179.2	(0.1)
Effect of currency rate changes on cash	0	0
Net increase in cash and cash equivalents	120.9	(21.6)
Cash and cash equivalents at beginning of period	18.5	56.5
Cash and cash equivalents at end of period	139.4	34.9
Other Subsidiaries
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities	240.4	47.1
Cash Flows From Investing Activities:
Capital expenditures	(22.3)	(21.7)
Intercompany loan investment	(170.6)	0.1
Investment in subsidiary	0
Restricted cash	0.4	4.1
Other	1.0	5.0
Net cash used in investing activities	(191.5)	(12.5)
Cash Flows From Financing Activities:
Repayment of external debt and capital leases	(4.5)	(0.3)
Excess tax benefit from share-based compensation	8.9	1.3
Proceeds from exercise of share options	0	0
Repurchase of shares	0	0
Intercompany loan borrowings, net	0	0
Capital contribution	20.0
Other		(0.2)
Net cash (used in) provided by financing activities	24.4	0.8
Effect of currency rate changes on cash	(3.9)	(1.4)
Net increase in cash and cash equivalents	69.4	34.0
Cash and cash equivalents at beginning of period	689.0	217.8
Cash and cash equivalents at end of period	758.4	251.8
Eliminations
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities	0	0
Cash Flows From Investing Activities:
Capital expenditures	0	0
Intercompany loan investment	182.5	1.4
Investment in subsidiary	20.0
Restricted cash	0	0
Other	0	0
Net cash used in investing activities	202.5	1.4
Cash Flows From Financing Activities:
Repayment of external debt and capital leases	0	0
Excess tax benefit from share-based compensation	0	0
Proceeds from exercise of share options	0	0
Repurchase of shares	0	0
Intercompany loan borrowings, net	(182.5)	(1.4)
Capital contribution	(20.0)
Other		0
Net cash (used in) provided by financing activities	(202.5)	(1.4)
Effect of currency rate changes on cash	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	$ 0	$ 0

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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