Condensed Consolidating and Combining Financial Statements (Schedule of Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Current Assets:
Cash and cash equivalents	$ 280.5	$ 365.9	$ 707.8	$ 275.5
Accounts receivable, net	465.8	489.6
Inventories	335.6	262.1
Deferred income taxes	0.0	139.2
Prepaid expenses and other current assets	115.9	194.4
Current assets held for sale	308.8	394.9
Intercompany receivable	0.0	0.0
Total current assets	1,506.6	1,846.1
Property, plant and equipment, net	844.0	793.0
Goodwill	3,705.3	3,649.4
Intangible assets, net	9,182.3	9,666.3
Long-term assets held for sale	0.0	223.6
Investment in subsidiaries	0.0	0.0
Intercompany loan receivable	0.0	0.0
Other assets	260.5	225.7
Total Assets	15,498.7	16,404.1
Current Liabilities:
Current maturities of long-term debt	256.3	22.0
Accounts payable	110.1	116.8
Accrued payroll and payroll-related costs	116.0	95.0
Accrued interest	80.6	80.2
Accrued and other current liabilities	550.9	486.1
Current liabilities held for sale	120.8	129.3
Intercompany payable	0.0	0.0
Total current liabilities	1,234.7	929.4
Long-term debt	5,788.7	6,474.3
Pension and postretirement benefits	144.9	114.2
Environmental liabilities	73.4	73.3
Deferred income taxes	2,581.4	3,117.5
Other income tax liabilities	67.7	121.3
Long-term liabilities held for sale	0.0	53.9
Intercompany loans payable	0.0	0.0
Other liabilities	337.2	209.0
Total Liabilities	10,228.0	11,092.9
Shareholders' equity	5,270.7	5,311.2	4,958.0	1,255.6
Total Liabilities and Shareholders' Equity	15,498.7	16,404.1
Mallinckrodt plc
Current Assets:
Cash and cash equivalents	0.3	0.1	0.3	1.2
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	1.4	1.3
Current assets held for sale	0.0	0.0
Intercompany receivable	88.9	39.1
Total current assets	90.6	40.5
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	5,657.8	14,797.7
Intercompany loan receivable	143.5	174.4
Other assets	0.0	0.0
Total Assets	5,891.9	15,012.6
Current Liabilities:
Current maturities of long-term debt	0.0	0.0
Accounts payable	0.2	0.0
Accrued payroll and payroll-related costs	0.0	0.1
Accrued interest	0.0	0.0
Accrued and other current liabilities	2.2	1.8
Current liabilities held for sale	0.0	0.0
Intercompany payable	618.8	9,699.5
Total current liabilities	621.2	9,701.4
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	621.2	9,701.4
Shareholders' equity	5,270.7	5,311.2
Total Liabilities and Shareholders' Equity	5,891.9	15,012.6
Mallinckrodt International Finance S.A.
Current Assets:
Cash and cash equivalents	25.0	152.1	18.5	56.5
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	0.1	0.2
Current assets held for sale	0.0	0.0
Intercompany receivable	473.8	128.6
Total current assets	498.9	280.9
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	20,168.4	18,838.6
Intercompany loan receivable	0.0	0.0
Other assets	0.0	0.1
Total Assets	20,667.3	19,119.6
Current Liabilities:
Current maturities of long-term debt	19.8	20.0
Accounts payable	0.0	0.2
Accrued payroll and payroll-related costs	0.0	0.0
Accrued interest	79.3	77.1
Accrued and other current liabilities	7.5	0.3
Current liabilities held for sale	0.0	0.0
Intercompany payable	462.6	0.0
Total current liabilities	569.2	97.6
Long-term debt	5,767.8	6,299.4
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	3,302.9	2,672.6
Other liabilities	7.4	0.0
Total Liabilities	9,647.3	9,069.6
Shareholders' equity	11,020.0	10,050.0
Total Liabilities and Shareholders' Equity	20,667.3	19,119.6
Other Subsidiaries
Current Assets:
Cash and cash equivalents	255.2	213.7	689.0	217.8
Accounts receivable, net	465.8	489.6
Inventories	335.6	262.1
Deferred income taxes	0.0	139.2
Prepaid expenses and other current assets	114.4	192.9
Current assets held for sale	308.8	394.9
Intercompany receivable	1,081.4	9,699.5
Total current assets	2,561.2	11,391.9
Property, plant and equipment, net	844.0	793.0
Goodwill	3,705.3	3,649.4
Intangible assets, net	9,182.3	9,666.3
Long-term assets held for sale	0.0	223.6
Investment in subsidiaries	11,020.0	10,050.0
Intercompany loan receivable	3,159.4	2,498.2
Other assets	260.5	225.6
Total Assets	30,732.7	38,498.0
Current Liabilities:
Current maturities of long-term debt	236.5	2.0
Accounts payable	109.9	116.6
Accrued payroll and payroll-related costs	116.0	94.9
Accrued interest	1.3	3.1
Accrued and other current liabilities	541.2	484.0
Current liabilities held for sale	120.8	129.3
Intercompany payable	562.7	167.7
Total current liabilities	1,688.4	997.6
Long-term debt	20.9	174.9
Pension and postretirement benefits	144.9	114.2
Environmental liabilities	73.4	73.3
Deferred income taxes	2,581.4	3,117.5
Other income tax liabilities	67.7	121.3
Long-term liabilities held for sale	0.0	53.9
Intercompany loans payable	0.0	0.0
Other liabilities	329.8	209.0
Total Liabilities	4,906.5	4,861.7
Shareholders' equity	25,826.2	33,636.3
Total Liabilities and Shareholders' Equity	30,732.7	38,498.0
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	(1,644.1)	(9,867.2)
Total current assets	(1,644.1)	(9,867.2)
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	(36,846.2)	(43,686.3)
Intercompany loan receivable	(3,302.9)	(2,672.6)
Other assets	0.0	0.0
Total Assets	(41,793.2)	(56,226.1)
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 interest	0.0	0.0
Accrued and other current liabilities	0.0	0.0
Current liabilities held for sale	0.0	0.0
Intercompany payable	(1,644.1)	(9,867.2)
Total current liabilities	(1,644.1)	(9,867.2)
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	(3,302.9)	(2,672.6)
Other liabilities	0.0	0.0
Total Liabilities	(4,947.0)	(12,539.8)
Shareholders' equity	(36,846.2)	(43,686.3)
Total Liabilities and Shareholders' Equity	$ (41,793.2)	$ (56,226.1)