Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 29, 2019	Mar. 30, 2018
Condensed Consolidating Financial Statements
Net sales		$ 790.6	$ 755.3
Cost of sales		455.5	407.8
Gross profit		335.1	347.5
Selling, general and administrative expenses		230.2	211.2
Research and development expenses		85.3	82.0
Restructuring charges, net		4.2	28.2
Operating income	[1]	15.4	26.1
Interest expense		(82.7)	(91.4)
Interest income		1.5	3.2
Other income, net		16.3	4.6
Intercompany Interest And Fees		0.0	0.0
Income (Loss) from Equity Method Investments		0.0	0.0
Loss from continuing operations before income taxes		(49.5)	(57.5)
Income tax benefit		(204.7)	(36.6)
Income (Loss) from Continuing Operations		155.2	(20.9)
(Loss) income from discontinued operations, net of income taxes		(0.3)	2.9
Net Income (Loss)		154.9	(18.0)
Other Comprehensive Income (Loss), Net of Tax		1.3	(2.4)
Comprehensive Income (Loss)		156.2	(20.4)
Mallinckrodt plc
Condensed Consolidating Financial Statements
Net sales		0.0	0.0
Cost of sales		0.6	0.2
Gross profit		(0.6)	(0.2)
Selling, general and administrative expenses		11.3	6.4
Research and development expenses		1.4	0.5
Restructuring charges, net		0.0	0.0
Operating income		(13.3)	(7.1)
Interest expense		(11.1)	(3.0)
Interest income		12.2	2.2
Other income, net		3.2	6.1
Intercompany Interest And Fees		(6.5)	(4.5)
Income (Loss) from Equity Method Investments		169.3	(12.9)
Loss from continuing operations before income taxes		153.8	(19.2)
Income tax benefit		(1.1)	(1.2)
Income (Loss) from Continuing Operations		154.9	(18.0)
(Loss) income from discontinued operations, net of income taxes		0.0	0.0
Net Income (Loss)		154.9	(18.0)
Other Comprehensive Income (Loss), Net of Tax		1.3	(2.4)
Comprehensive Income (Loss)		156.2	(20.4)
Mallinckrodt International Finance S.A.
Condensed Consolidating Financial Statements
Net sales		0.0	0.0
Cost of sales		0.0	0.0
Gross profit		0.0	0.0
Selling, general and administrative expenses		0.2	0.2
Research and development expenses		0.0	0.0
Restructuring charges, net		0.0	0.0
Operating income		(0.2)	(0.2)
Interest expense		(70.3)	(101.2)
Interest income		0.1	1.7
Other income, net		1.2	2.8
Intercompany Interest And Fees		0.0	0.0
Income (Loss) from Equity Method Investments		298.4	175.4
Loss from continuing operations before income taxes		229.2	78.5
Income tax benefit		0.0	(0.8)
Income (Loss) from Continuing Operations		229.2	79.3
(Loss) income from discontinued operations, net of income taxes		(0.2)	(0.1)
Net Income (Loss)		229.0	79.2
Other Comprehensive Income (Loss), Net of Tax		1.3	(2.4)
Comprehensive Income (Loss)		230.3	76.8
Other Subsidiaries
Condensed Consolidating Financial Statements
Net sales		790.6	755.3
Cost of sales		454.9	407.6
Gross profit		335.7	347.7
Selling, general and administrative expenses		218.7	204.6
Research and development expenses		83.9	81.5
Restructuring charges, net		4.2	28.2
Operating income		28.9	33.4
Interest expense		(39.0)	(7.1)
Interest income		26.9	19.2
Other income, net		11.9	(4.3)
Intercompany Interest And Fees		6.5	4.5
Income (Loss) from Equity Method Investments		229.0	79.2
Loss from continuing operations before income taxes		264.2	124.9
Income tax benefit		(203.6)	(34.6)
Income (Loss) from Continuing Operations		467.8	159.5
(Loss) income from discontinued operations, net of income taxes		(0.1)	3.0
Net Income (Loss)		467.7	162.5
Other Comprehensive Income (Loss), Net of Tax		2.4	(5.2)
Comprehensive Income (Loss)		470.1	157.3
Eliminations
Condensed Consolidating Financial Statements
Net sales		0.0	0.0
Cost of sales		0.0	0.0
Gross profit		0.0	0.0
Selling, general and administrative expenses		0.0	0.0
Research and development expenses		0.0	0.0
Restructuring charges, net		0.0	0.0
Operating income		0.0	0.0
Interest expense		37.7	19.9
Interest income		(37.7)	(19.9)
Other income, net		0.0	0.0
Intercompany Interest And Fees		0.0	0.0
Income (Loss) from Equity Method Investments		(696.7)	(241.7)
Loss from continuing operations before income taxes		(696.7)	(241.7)
Income tax benefit		0.0	0.0
Income (Loss) from Continuing Operations		(696.7)	(241.7)
(Loss) income from discontinued operations, net of income taxes		0.0	0.0
Net Income (Loss)		(696.7)	(241.7)
Other Comprehensive Income (Loss), Net of Tax		(3.7)	7.6
Comprehensive Income (Loss)		$ (700.4)	$ (234.1)

[1] The amount of operating loss included in the Company's unaudited condensed statement of income for the three months ended March 30, 2018 related to the Sucampo Acquisition was $30.7 million. Included within these results were $9.1 million of amortization associated with intangibles recognized from this acquisition and $15.0 million of expense associated with fair value adjustments of acquired inventory.