Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 30, 2018	Mar. 31, 2017
Condensed Consolidating Financial Statements
Net sales	$ 572.6	$ 560.0
Cost of sales	295.8	259.9
Gross profit	276.8	300.1
Selling, general and administrative expenses	192.4	217.6
Research and development expenses	64.1	45.0
Restructuring charges, net	23.1	10.3
Non-restructuring impairment charges	0.0
Losses (gains) on divestiture and license	0.0	(59.1)
Operating (loss) income	(2.8)	86.3
Interest expense	(91.4)	(94.2)
Interest income	3.2	0.9
Other income (expense), net	4.6	(79.9)
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	(86.4)	(86.9)
Income tax benefit	(43.4)	(42.0)
Income (Loss) from Continuing Operations	(43.0)	(44.9)
Income from discontinued operations, net of income taxes	25.0	444.1
Net Income (Loss)	(18.0)	399.2
Other Comprehensive Income (Loss), Net of Tax	(2.4)	62.6
Comprehensive Income (Loss)	(20.4)	461.8
Mallinckrodt plc
Condensed Consolidating Financial Statements
Net sales	0.0	0.0
Cost of sales	0.2	0.0
Gross profit	(0.2)	0.0
Selling, general and administrative expenses	6.4	16.9
Research and development expenses	0.5	0.0
Restructuring charges, net	0.0	0.0
Non-restructuring impairment charges	0.0
Losses (gains) on divestiture and license	0.0	0.0
Operating (loss) income	(7.1)	(16.9)
Interest expense	(3.0)	(3.3)
Interest income	2.2	1.1
Other income (expense), net	6.1	15.4
Intercompany Interest And Fees	(4.5)	(5.5)
Income (Loss) from Equity Method Investments	(12.9)	408.7
Loss from continuing operations before income taxes	(19.2)	399.5
Income tax benefit	(1.2)	(2.0)
Income (Loss) from Continuing Operations	(18.0)	401.5
Income from discontinued operations, net of income taxes	0.0	(2.3)
Net Income (Loss)	(18.0)	399.2
Other Comprehensive Income (Loss), Net of Tax	(2.4)	62.6
Comprehensive Income (Loss)	(20.4)	461.8
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
Non-restructuring impairment charges	0.0
Losses (gains) on divestiture and license	0.0	0.0
Operating (loss) income	(0.2)	(0.2)
Interest expense	(101.2)	(85.3)
Interest income	1.7	0.3
Other income (expense), net	2.8	(9.9)
Intercompany Interest And Fees	0.0	0.0
Income (Loss) from Equity Method Investments	175.4	597.0
Loss from continuing operations before income taxes	78.5	501.9
Income tax benefit	(0.8)	(0.3)
Income (Loss) from Continuing Operations	79.3	502.2
Income from discontinued operations, net of income taxes	(0.1)	(1.7)
Net Income (Loss)	79.2	500.5
Other Comprehensive Income (Loss), Net of Tax	(2.4)	62.6
Comprehensive Income (Loss)	76.8	563.1
Other Subsidiaries
Condensed Consolidating Financial Statements
Net sales	572.6	560.0
Cost of sales	295.6	259.9
Gross profit	277.0	300.1
Selling, general and administrative expenses	185.8	200.5
Research and development expenses	63.6	45.0
Restructuring charges, net	23.1	10.3
Non-restructuring impairment charges	0.0
Losses (gains) on divestiture and license	0.0	(59.1)
Operating (loss) income	4.5	103.4
Interest expense	(7.1)	(20.2)
Interest income	19.2	14.1
Other income (expense), net	(4.3)	(85.4)
Intercompany Interest And Fees	4.5	5.5
Income (Loss) from Equity Method Investments	79.2	500.5
Loss from continuing operations before income taxes	96.0	517.9
Income tax benefit	(41.4)	(39.7)
Income (Loss) from Continuing Operations	137.4	557.6
Income from discontinued operations, net of income taxes	25.1	448.1
Net Income (Loss)	162.5	1,005.7
Other Comprehensive Income (Loss), Net of Tax	(5.2)	125.0
Comprehensive Income (Loss)	157.3	1,130.7
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
Non-restructuring impairment charges	0.0
Losses (gains) on divestiture and license	0.0	0.0
Operating (loss) income	0.0	0.0
Interest expense	19.9	14.6
Interest income	(19.9)	(14.6)
Other income (expense), net	0.0	0.0
Intercompany Interest And Fees	0.0	0.0
Income (Loss) from Equity Method Investments	(241.7)	(1,506.2)
Loss from continuing operations before income taxes	(241.7)	(1,506.2)
Income tax benefit	0.0	0.0
Income (Loss) from Continuing Operations	(241.7)	(1,506.2)
Income from discontinued operations, net of income taxes	0.0	0.0
Net Income (Loss)	(241.7)	(1,506.2)
Other Comprehensive Income (Loss), Net of Tax	7.6	(187.6)
Comprehensive Income (Loss)	$ (234.1)	$ (1,693.8)