Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Mar. 25, 2016	Sep. 25, 2015	Mar. 27, 2015	Sep. 26, 2014
Current Assets:
Cash and cash equivalents	$ 341.4	$ 365.9	$ 1,053.5	$ 707.8
Accounts receivable, net	503.5	548.5
Inventories	377.1	281.8
Deferred income taxes	116.3	142.7
Prepaid expenses and other current assets	205.6	207.3
Current assets held for sale	1.0	299.9
Intercompany receivables	0.0	0.0
Total current assets	1,544.9	1,846.1
Property, plant and equipment, net	999.4	991.3
Goodwill	3,645.3	3,649.4
Intangible assets, net	9,425.3	9,666.3
Investment in subsidiaries	0.0	0.0
Intercompany loans receivable	0.0	0.0
Other assets	288.7	251.0
Total Assets	15,903.6	16,404.1
Current Liabilities:
Current maturities of long-term debt	21.6	22.3
Accounts payable	118.0	133.0
Accrued payroll and payroll-related costs	99.6	103.7
Accrued interest	98.3	80.2
Accrued and other current liabilities	549.5	517.4
Current liabilities held for sale	5.1	72.8
Intercompany payables	0.0	0.0
Total current liabilities	892.1	929.4
Long-term debt	6,409.6	6,474.3
Pension and postretirement benefits	132.7	116.7
Environmental liabilities	72.5	73.3
Deferred income taxes	2,872.2	3,132.4
Other income tax liabilities	118.3	121.3
Intercompany loans payable	0.0	0.0
Other liabilities	308.3	245.5
Total Liabilities	10,805.7	11,092.9
Shareholders' Equity	5,097.9	5,311.2
Total Liabilities and Shareholders' Equity	15,903.6	16,404.1
Mallinckrodt plc
Current Assets:
Cash and cash equivalents	0.1	0.1	2.0	0.3
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	0.8	1.3
Current assets held for sale	0.0	0.0
Intercompany receivables	38.9	39.1
Total current assets	39.8	40.5
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Investment in subsidiaries	15,133.9	14,797.7
Intercompany loans receivable	22.0	174.4
Other assets	0.0	0.0
Total Assets	15,195.7	15,012.6
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	0.1
Accrued interest	0.0	0.0
Accrued and other current liabilities	1.4	1.8
Current liabilities held for sale	0.0	0.0
Intercompany payables	10,096.4	9,699.5
Total current liabilities	10,097.8	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
Intercompany loans payable	0.0	0.0
Other liabilities	0.0	0.0
Total Liabilities	10,097.8	9,701.4
Shareholders' Equity	5,097.9	5,311.2
Total Liabilities and Shareholders' Equity	15,195.7	15,012.6
Mallinckrodt International Finance S.A.
Current Assets:
Cash and cash equivalents	137.9	152.1	270.0	18.5
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	0.3	0.2
Current assets held for sale	0.0	0.0
Intercompany receivables	4.4	128.6
Total current assets	142.6	280.9
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Investment in subsidiaries	19,316.0	18,838.6
Intercompany loans receivable	0.0	0.0
Other assets	0.0	0.1
Total Assets	19,458.6	19,119.6
Current Liabilities:
Current maturities of long-term debt	19.6	20.0
Accounts payable	0.3	0.2
Accrued payroll and payroll-related costs	0.0	0.0
Accrued interest	97.8	77.1
Accrued and other current liabilities	8.9	0.3
Current liabilities held for sale	0.0	0.0
Intercompany payables	633.3	0.0
Total current liabilities	759.9	97.6
Long-term debt	6,173.5	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
Intercompany loans payable	2,011.0	2,672.6
Other liabilities	6.9	0.0
Total Liabilities	8,951.3	9,069.6
Shareholders' Equity	10,507.3	10,050.0
Total Liabilities and Shareholders' Equity	19,458.6	19,119.6
Other Subsidiaries
Current Assets:
Cash and cash equivalents	203.4	213.7	781.5	689.0
Accounts receivable, net	503.5	548.5
Inventories	377.1	281.8
Deferred income taxes	116.3	142.7
Prepaid expenses and other current assets	204.5	205.8
Current assets held for sale	1.0	299.9
Intercompany receivables	10,729.7	9,699.5
Total current assets	12,135.5	11,391.9
Property, plant and equipment, net	999.4	991.3
Goodwill	3,645.3	3,649.4
Intangible assets, net	9,425.3	9,666.3
Investment in subsidiaries	10,507.3	10,050.0
Intercompany loans receivable	1,989.0	2,498.2
Other assets	288.7	250.9
Total Assets	38,990.5	38,498.0
Current Liabilities:
Current maturities of long-term debt	2.0	2.3
Accounts payable	117.7	132.8
Accrued payroll and payroll-related costs	99.6	103.6
Accrued interest	0.5	3.1
Accrued and other current liabilities	539.2	515.3
Current liabilities held for sale	5.1	72.8
Intercompany payables	43.3	167.7
Total current liabilities	807.4	997.6
Long-term debt	236.1	174.9
Pension and postretirement benefits	132.7	116.7
Environmental liabilities	72.5	73.3
Deferred income taxes	2,872.2	3,132.4
Other income tax liabilities	118.3	121.3
Intercompany loans payable	0.0	0.0
Other liabilities	301.4	245.5
Total Liabilities	4,540.6	4,861.7
Shareholders' Equity	34,449.9	33,636.3
Total Liabilities and Shareholders' Equity	38,990.5	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 receivables	(10,773.0)	(9,867.2)
Total current assets	(10,773.0)	(9,867.2)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Investment in subsidiaries	(44,957.2)	(43,686.3)
Intercompany loans receivable	(2,011.0)	(2,672.6)
Other assets	0.0	0.0
Total Assets	(57,741.2)	(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 payables	(10,773.0)	(9,867.2)
Total current liabilities	(10,773.0)	(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
Intercompany loans payable	(2,011.0)	(2,672.6)
Other liabilities	0.0	0.0
Total Liabilities	(12,784.0)	(12,539.8)
Shareholders' Equity	(44,957.2)	(43,686.3)
Total Liabilities and Shareholders' Equity	$ (57,741.2)	$ (56,226.1)