Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Mar. 30, 2018	Dec. 29, 2017	Mar. 31, 2017
Current Assets:
Cash and cash equivalents	$ 511.9	$ 1,260.9	$ 259.8
Accounts receivable, net	321.5	275.4
Inventories	213.4	128.7
Prepaid expenses and other current assets	114.9	74.7
Notes receivable	0.0	154.0
Current assets held for sale	1,143.0	391.5
Intercompany receivables	0.0	0.0
Total current assets	2,304.7	2,285.2
Property, plant and equipment, net	426.7	413.2
Goodwill	3,674.0	3,482.7
Intangible assets, net	8,953.8	8,261.0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	0.0	742.7
Investment in subsidiaries	0.0	0.0
Intercompany loans receivable	0.0	0.0
Other assets	157.3	156.2
Total Assets	15,516.5	15,341.0
Current Liabilities:
Current maturities of long-term debt	322.1	313.7
Accounts payable	96.9	77.3
Accrued payroll and payroll-related costs	50.1	78.4
Accrued interest	81.5	57.0
Income taxes payable	20.2	15.5
Accrued and other current liabilities	368.0	368.5
Current liabilities held for sale	159.7	140.0
Intercompany payables	0.0	0.0
Total current liabilities	1,098.5	1,050.4
Long-term debt	6,491.5	6,420.9
Pension and postretirement benefits	66.8	67.1
Environmental liabilities	61.9	62.8
Deferred income taxes	871.3	749.1
Other income tax liabilities	125.3	94.1
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	0.0	22.6
Intercompany loans payable	0.0	0.0
Other liabilities	339.9	352.0
Total Liabilities	9,055.2	8,819.0
Shareholders' Equity	6,461.3	6,522.0
Total Liabilities and Shareholders' Equity	15,516.5	15,341.0
Mallinckrodt plc
Current Assets:
Cash and cash equivalents	1.4	0.7	0.4
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	0.6	1.0
Notes receivable	0.0	0.0
Current assets held for sale	0.0	0.0
Intercompany receivables	131.5	70.0
Total current assets	133.5	71.7
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent		0.0
Investment in subsidiaries	6,037.4	6,551.6
Intercompany loans receivable	517.1	593.1
Other assets	0.0	0.0
Total Assets	6,688.0	7,216.4
Current Liabilities:
Current maturities of long-term debt	0.0	0.0
Accounts payable	0.1	0.1
Accrued payroll and payroll-related costs	0.0	0.0
Accrued interest	0.0	0.0
Income taxes payable	0.0	0.0
Accrued and other current liabilities	1.6	0.8
Current liabilities held for sale	0.0	0.0
Intercompany payables	225.0	693.5
Total current liabilities	226.7	694.4
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
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		0.0
Intercompany loans payable	0.0	0.0
Other liabilities	0.0	0.0
Total Liabilities	226.7	694.4
Shareholders' Equity	6,461.3	6,522.0
Total Liabilities and Shareholders' Equity	6,688.0	7,216.4
Mallinckrodt International Finance S.A.
Current Assets:
Cash and cash equivalents	212.8	908.8	130.3
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	0.4	0.2
Notes receivable	0.0	0.0
Current assets held for sale	0.0	0.0
Intercompany receivables	25.3	173.4
Total current assets	238.5	1,082.4
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent		0.0
Investment in subsidiaries	23,408.7	23,217.8
Intercompany loans receivable	0.0	0.0
Other assets	0.0	0.0
Total Assets	23,647.2	24,300.2
Current Liabilities:
Current maturities of long-term debt	322.0	313.5
Accounts payable	0.2	0.0
Accrued payroll and payroll-related costs	0.0	0.0
Accrued interest	80.9	53.0
Income taxes payable	0.0	0.0
Accrued and other current liabilities	0.7	0.4
Current liabilities held for sale	0.0	0.0
Intercompany payables	19.3	104.6
Total current liabilities	423.1	471.5
Long-term debt	6,256.1	6,206.8
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
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		0.0
Intercompany loans payable	5,340.3	5,257.9
Other liabilities	7.8	7.8
Total Liabilities	12,027.3	11,944.0
Shareholders' Equity	11,619.9	12,356.2
Total Liabilities and Shareholders' Equity	23,647.2	24,300.2
Other Subsidiaries
Current Assets:
Cash and cash equivalents	297.7	351.4	129.1
Accounts receivable, net	321.5	275.4
Inventories	213.4	128.7
Prepaid expenses and other current assets	113.9	73.5
Notes receivable	0.0	154.0
Current assets held for sale	1,143.0	391.5
Intercompany receivables	281.3	831.4
Total current assets	2,370.8	2,205.9
Property, plant and equipment, net	426.7	413.2
Goodwill	3,674.0	3,482.7
Intangible assets, net	8,953.8	8,261.0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent		742.7
Investment in subsidiaries	11,619.9	12,356.2
Intercompany loans receivable	4,823.2	4,664.8
Other assets	157.3	156.2
Total Assets	32,025.7	32,282.7
Current Liabilities:
Current maturities of long-term debt	0.1	0.2
Accounts payable	96.6	77.2
Accrued payroll and payroll-related costs	50.1	78.4
Accrued interest	0.6	4.0
Income taxes payable	20.2	15.5
Accrued and other current liabilities	365.7	367.3
Current liabilities held for sale	159.7	140.0
Intercompany payables	193.8	276.7
Total current liabilities	886.8	959.3
Long-term debt	235.4	214.1
Pension and postretirement benefits	66.8	67.1
Environmental liabilities	61.9	62.8
Deferred income taxes	871.3	749.1
Other income tax liabilities	125.3	94.1
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		22.6
Intercompany loans payable	0.0	0.0
Other liabilities	332.1	344.2
Total Liabilities	2,579.6	2,513.3
Shareholders' Equity	29,446.1	29,769.4
Total Liabilities and Shareholders' Equity	32,025.7	32,282.7
Eliminations
Current Assets:
Cash and cash equivalents	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
Notes receivable	0.0	0.0
Current assets held for sale	0.0	0.0
Intercompany receivables	(438.1)	(1,074.8)
Total current assets	(438.1)	(1,074.8)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent		0.0
Investment in subsidiaries	(41,066.0)	(42,125.6)
Intercompany loans receivable	(5,340.3)	(5,257.9)
Other assets	0.0	0.0
Total Assets	(46,844.4)	(48,458.3)
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
Income taxes payable	0.0	0.0
Accrued and other current liabilities	0.0	0.0
Current liabilities held for sale	0.0	0.0
Intercompany payables	(438.1)	(1,074.8)
Total current liabilities	(438.1)	(1,074.8)
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
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		0.0
Intercompany loans payable	(5,340.3)	(5,257.9)
Other liabilities	0.0	0.0
Total Liabilities	(5,778.4)	(6,332.7)
Shareholders' Equity	(41,066.0)	(42,125.6)
Total Liabilities and Shareholders' Equity	(46,844.4)	(48,458.3)
Ordinary A
Condensed Consolidating Financial Statements
Ordinary A shares	$ 0.0	$ 0.0