Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 30, 2016	Sep. 30, 2016	Dec. 25, 2015	Sep. 25, 2015
Current Assets:
Cash and cash equivalents	$ 342.0	$ 280.5	$ 521.9	$ 365.9
Accounts receivable, net	431.0	465.8
Inventories	350.7	335.6
Prepaid expenses and other current assets	131.9	115.9
Current assets held for sale	310.9	308.8
Intercompany receivables	0.0	0.0
Total current assets	1,566.5	1,506.6
Property, plant and equipment, net	881.5	844.0
Goodwill	3,498.1	3,705.3
Intangible assets, net	9,000.5	9,182.3
Investment in subsidiaries	0.0	0.0
Intercompany loans receivable	0.0	0.0
Other assets	259.7	260.5
Total Assets	15,206.3	15,498.7
Current Liabilities:
Current maturities of long-term debt	271.2	256.3
Accounts payable	112.1	110.1
Accrued payroll and payroll-related costs	76.1	116.0
Accrued interest	68.7	80.6
Accrued and other current liabilities	658.8	550.9
Current liabilities held for sale	120.3	120.8
Intercompany payables	0.0	0.0
Total current liabilities	1,307.2	1,234.7
Long-term debt	5,880.8	5,788.7
Pension and postretirement benefits	136.4	144.9
Environmental liabilities	73.0	73.4
Deferred income taxes	2,398.1	2,581.4
Other income tax liabilities	70.4	67.7
Intercompany loans payable	0.0	0.0
Other liabilities	356.1	337.2
Total Liabilities	10,222.0	10,228.0
Shareholders' Equity	4,984.3	5,270.7
Total Liabilities and Shareholders' Equity	15,206.3	15,498.7
Mallinckrodt plc
Current Assets:
Cash and cash equivalents	0.5	0.3	0.3	0.1
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	1.0	1.4
Current assets held for sale	0.0	0.0
Intercompany receivables	59.7	88.9
Total current assets	61.2	90.6
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Investment in subsidiaries	5,534.1	5,657.8
Intercompany loans receivable	3.5	143.5
Other assets	0.0	0.0
Total Assets	5,598.8	5,891.9
Current Liabilities:
Current maturities of long-term debt	0.0	0.0
Accounts payable	0.1	0.2
Accrued payroll and payroll-related costs	0.0	0.0
Accrued interest	0.0	0.0
Accrued and other current liabilities	1.9	2.2
Current liabilities held for sale	0.0	0.0
Intercompany payables	612.5	618.8
Total current liabilities	614.5	621.2
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
Intercompany loans payable	0.0	0.0
Other liabilities	0.0	0.0
Total Liabilities	614.5	621.2
Shareholders' Equity	4,984.3	5,270.7
Total Liabilities and Shareholders' Equity	5,598.8	5,891.9
Mallinckrodt International Finance S.A.
Current Assets:
Cash and cash equivalents	44.5	25.0	158.5	152.1
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	0.0	0.1
Current assets held for sale	0.0	0.0
Intercompany receivables	65.1	473.8
Total current assets	109.6	498.9
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Investment in subsidiaries	20,624.1	20,168.4
Intercompany loans receivable	0.0	0.0
Other assets	0.0	0.0
Total Assets	20,733.7	20,667.3
Current Liabilities:
Current maturities of long-term debt	19.7	19.8
Accounts payable	0.1	0.0
Accrued payroll and payroll-related costs	0.0	0.0
Accrued interest	53.9	79.3
Accrued and other current liabilities	7.5	7.5
Current liabilities held for sale	0.0	0.0
Intercompany payables	467.1	462.6
Total current liabilities	548.3	569.2
Long-term debt	5,860.6	5,767.8
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
Intercompany loans payable	3,329.4	3,302.9
Other liabilities	7.0	7.4
Total Liabilities	9,745.3	9,647.3
Shareholders' Equity	10,988.4	11,020.0
Total Liabilities and Shareholders' Equity	20,733.7	20,667.3
Other Subsidiaries
Current Assets:
Cash and cash equivalents	297.0	255.2	363.1	213.7
Accounts receivable, net	431.0	465.8
Inventories	350.7	335.6
Prepaid expenses and other current assets	130.9	114.4
Current assets held for sale	310.9	308.8
Intercompany receivables	1,081.3	1,081.4
Total current assets	2,601.8	2,561.2
Property, plant and equipment, net	881.5	844.0
Goodwill	3,498.1	3,705.3
Intangible assets, net	9,000.5	9,182.3
Investment in subsidiaries	10,988.5	11,020.0
Intercompany loans receivable	3,325.9	3,159.4
Other assets	259.7	260.5
Total Assets	30,556.0	30,732.7
Current Liabilities:
Current maturities of long-term debt	251.5	236.5
Accounts payable	111.9	109.9
Accrued payroll and payroll-related costs	76.1	116.0
Accrued interest	14.8	1.3
Accrued and other current liabilities	649.4	541.2
Current liabilities held for sale	120.3	120.8
Intercompany payables	126.5	562.7
Total current liabilities	1,350.5	1,688.4
Long-term debt	20.2	20.9
Pension and postretirement benefits	136.4	144.9
Environmental liabilities	73.0	73.4
Deferred income taxes	2,398.1	2,581.4
Other income tax liabilities	70.4	67.7
Intercompany loans payable	0.0	0.0
Other liabilities	349.1	329.8
Total Liabilities	4,397.7	4,906.5
Shareholders' Equity	26,158.3	25,826.2
Total Liabilities and Shareholders' Equity	30,556.0	30,732.7
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
Prepaid expenses and other current assets	0.0	0.0
Current assets held for sale	0.0	0.0
Intercompany receivables	(1,206.1)	(1,644.1)
Total current assets	(1,206.1)	(1,644.1)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Investment in subsidiaries	(37,146.7)	(36,846.2)
Intercompany loans receivable	(3,329.4)	(3,302.9)
Other assets	0.0	0.0
Total Assets	(41,682.2)	(41,793.2)
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 payables	(1,206.1)	(1,644.1)
Total current liabilities	(1,206.1)	(1,644.1)
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
Intercompany loans payable	(3,329.4)	(3,302.9)
Other liabilities	0.0	0.0
Total Liabilities	(4,535.5)	(4,947.0)
Shareholders' Equity	(37,146.7)	(36,846.2)
Total Liabilities and Shareholders' Equity	$ (41,682.2)	$ (41,793.2)