Condensed Consolidating and Combining Financial Statements (Schedule of Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013	Sep. 28, 2012
Current Assets:
Cash and cash equivalents	$ 365.9	$ 707.8	$ 275.5	$ 0.0
Accounts receivable, net	548.5	476.6
Inventories	281.8	306.4
Deferred income taxes	142.7	152.3
Prepaid expenses and other current assets	207.3	227.1
Current assets held for sale	299.9	200.8
Intercompany receivable	0.0	0.0
Total current assets	1,846.1	2,071.0
Property, plant and equipment, net	991.3	886.8
Goodwill	3,649.4	2,401.9
Intangible assets, net	9,666.3	7,082.2
Long-term assets held for sale	0.0	111.2
Investment in subsidiaries	0.0	0.0
Intercompany loan receivable	0.0	0.0
Other assets	251.0	234.2
Total Assets	16,404.1	12,787.3
Current Liabilities:
Current maturities of long-term debt	22.3	21.2
Accounts payable	133.0	110.7
Accrued payroll and payroll-related costs	103.7	116.3
Accrued royalties	29.3	67.7
Accrued and other current liabilities	568.3	529.9
Current liabilities held for sale	72.8	59.0
Intercompany payable	0.0	0.0
Total current liabilities	929.4	904.8
Long-term debt	6,474.3	3,874.0
Pension and postretirement benefits	116.7	116.2
Environmental liabilities	73.3	59.2
Deferred income taxes	3,132.4	2,399.6
Other income tax liabilities	121.3	122.6
Long-term liabilities held for sale	0.0	9.7
Intercompany loans payable	0.0	0.0
Other liabilities	245.5	343.2
Total Liabilities	11,092.9	7,829.3
Shareholders' equity	5,311.2	4,958.0	1,255.6	1,891.9
Total Liabilities and Shareholders' Equity	16,404.1	12,787.3
Mallinckrodt plc
Current Assets:
Cash and cash equivalents	0.1	0.3	1.2	0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Deferred income taxes	0.0	0.0
Prepaid expenses and other current assets	1.3	0.5
Current assets held for sale	0.0	0.0
Intercompany receivable	39.1	13.5
Total current assets	40.5	14.3
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Long-term assets held for sale	0.0	0.0
Investment in subsidiaries	14,797.7	586.8
Intercompany loan receivable	174.4	4,385.0
Other assets	0.0	0.0
Total Assets	15,012.6	4,986.1
Current Liabilities:
Current maturities of long-term debt	0.0	0.0
Accounts payable	0.0	1.2
Accrued payroll and payroll-related costs	0.1	0.1
Accrued royalties	0.0	0.0
Accrued and other current liabilities	1.8	1.1
Current liabilities held for sale	0.0	0.0
Intercompany payable	9,699.5	25.7
Total current liabilities	9,701.4	28.1
Long-term debt	0.0	0.0
Pension and postretirement benefits	0.0	0.0
Environmental liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Other income tax liabilities	0.0	0.0
Long-term liabilities held for sale	0.0	0.0
Intercompany loans payable	0.0	0.0
Other liabilities	0.0	0.0
Total Liabilities	9,701.4	28.1
Shareholders' equity	5,311.2	4,958.0
Total Liabilities and Shareholders' Equity	15,012.6	4,986.1
Mallinckrodt International Finance S.A.
Current Assets:
Cash and cash equivalents	152.1	18.5	56.5	0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Deferred income taxes	0.0	0.0
Prepaid expenses and other current assets	0.2	10.8
Current assets held for sale	0.0	0.0
Intercompany receivable	128.6	0.0
Total current assets	280.9	29.3
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Long-term assets held for sale	0.0	0.0
Investment in subsidiaries	18,838.6	10,645.7
Intercompany loan receivable	0.0	0.0
Other assets	0.1	0.0
Total Assets	19,119.6	10,675.0
Current Liabilities:
Current maturities of long-term debt	20.0	18.2
Accounts payable	0.2	0.2
Accrued payroll and payroll-related costs	0.0	0.0
Accrued royalties	0.0	0.0
Accrued and other current liabilities	77.4	50.9
Current liabilities held for sale	0.0	0.0
Intercompany payable	0.0	0.0
Total current liabilities	97.6	69.3
Long-term debt	6,299.4	3,693.9
Pension and postretirement benefits	0.0	0.0
Environmental liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Other income tax liabilities	0.0	0.0
Long-term liabilities held for sale	0.0	0.0
Intercompany loans payable	2,672.6	1,966.6
Other liabilities	0.0	0.0
Total Liabilities	9,069.6	5,729.8
Shareholders' equity	10,050.0	4,945.2
Total Liabilities and Shareholders' Equity	19,119.6	10,675.0
Other Subsidiaries
Current Assets:
Cash and cash equivalents	213.7	689.0	217.8	0.0
Accounts receivable, net	548.5	476.6
Inventories	281.8	306.4
Deferred income taxes	142.7	152.3
Prepaid expenses and other current assets	205.8	215.8
Current assets held for sale	299.9	200.8
Intercompany receivable	9,699.5	25.7
Total current assets	11,391.9	2,066.6
Property, plant and equipment, net	991.3	886.8
Goodwill	3,649.4	2,401.9
Intangible assets, net	9,666.3	7,082.2
Long-term assets held for sale	0.0	111.2
Investment in subsidiaries	10,050.0	4,945.1
Intercompany loan receivable	2,498.2	1,941.6
Other assets	250.9	234.2
Total Assets	38,498.0	19,669.6
Current Liabilities:
Current maturities of long-term debt	2.3	3.0
Accounts payable	132.8	109.3
Accrued payroll and payroll-related costs	103.6	116.2
Accrued royalties	29.3	67.7
Accrued and other current liabilities	489.1	477.9
Current liabilities held for sale	72.8	59.0
Intercompany payable	167.7	13.5
Total current liabilities	997.6	846.6
Long-term debt	174.9	180.1
Pension and postretirement benefits	116.7	116.2
Environmental liabilities	73.3	59.2
Deferred income taxes	3,132.4	2,399.6
Other income tax liabilities	121.3	122.6
Long-term liabilities held for sale	0.0	9.7
Intercompany loans payable	0.0	4,360.0
Other liabilities	245.5	343.2
Total Liabilities	4,861.7	8,437.2
Shareholders' equity	33,636.3	11,232.4
Total Liabilities and Shareholders' Equity	38,498.0	19,669.6
Eliminations
Current Assets:
Cash and cash equivalents	0.0	0.0	$ 0.0	$ 0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Deferred income taxes	0.0	0.0
Prepaid expenses and other current assets	0.0	0.0
Current assets held for sale	0.0	0.0
Intercompany receivable	(9,867.2)	(39.2)
Total current assets	(9,867.2)	(39.2)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Long-term assets held for sale	0.0	0.0
Investment in subsidiaries	(43,686.3)	(16,177.6)
Intercompany loan receivable	(2,672.6)	(6,326.6)
Other assets	0.0	0.0
Total Assets	(56,226.1)	(22,543.4)
Current Liabilities:
Current maturities of long-term debt	0.0	0.0
Accounts payable	0.0	0.0
Accrued payroll and payroll-related costs	0.0	0.0
Accrued royalties	0.0	0.0
Accrued and other current liabilities	0.0	0.0
Current liabilities held for sale	0.0	0.0
Intercompany payable	(9,867.2)	(39.2)
Total current liabilities	(9,867.2)	(39.2)
Long-term debt	0.0	0.0
Pension and postretirement benefits	0.0	0.0
Environmental liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Other income tax liabilities	0.0	0.0
Long-term liabilities held for sale	0.0	0.0
Intercompany loans payable	(2,672.6)	(6,326.6)
Other liabilities	0.0	0.0
Total Liabilities	(12,539.8)	(6,365.8)
Shareholders' equity	(43,686.3)	(16,177.6)
Total Liabilities and Shareholders' Equity	$ (56,226.1)	$ (22,543.4)