Condensed Consolidating and Combining Financial Statements (Schedule of Condensed Consolidating and Combining Statements of Comprehensive Income) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 27, 2013	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Condensed Consolidating Financial Statements
Net sales		$ 882.4	$ 877.3	$ 819.0	$ 768.2	$ 673.7	$ 530.1	$ 448.7	$ 429.5	$ 3,346.9	$ 2,082.0	$ 1,712.3
Cost of sales										1,493.3	1,021.8	890.0
Gross profit		482.1	503.8	462.9	404.8	363.2	254.1	226.7	216.2	1,853.6	1,060.2	822.3
Selling, general and administrative expenses										1,169.8	745.0	495.9
Research and development expenses										185.1	163.5	157.9
Separation costs										0.0	9.6	74.2
Restructuring charges, net										40.4	81.4	23.7
Non-restructuring impairment charges										0.0	151.6	0.0
Gain on divestiture and license										(3.5)	(15.0)	(2.9)
Operating income (loss)										461.8	(75.9)	73.5
Interest expense										(255.6)	(82.6)	(19.5)
Interest income										1.0	1.5	0.3
Other income (expense), net										8.1	3.1	1.4
Intercompany interest and fees										0.0	0.0	0.0
Equity in net income of subsidiaries										0.0	0.0	0.0
Income (loss) from continuing operations before income taxes	[1]									215.3	(153.9)	55.7
Income Tax Expense (Benefit)	[1]									(92.9)	(10.1)	47.5
Income (loss) from continuing operations		90.0	55.6	75.2	87.4	(173.5)	(29.0)	20.2	38.5	308.2	(143.8)	8.2
Income (loss) from discontinued operations, net of income taxes		(14.8)	2.4	23.6	5.3	(178.9)	4.9	(8.6)	7.1	16.5	(175.5)	50.6
Net income (loss)		$ 75.2	$ 58.0	$ 98.8	$ 92.7	$ (352.4)	$ (24.1)	$ 11.6	$ 45.6	324.7	(319.3)	58.8
Other comprehensive loss, net of tax										(64.8)	(42.8)	28.4
Comprehensive income (loss)										259.9	(362.1)	87.2
Mallinckrodt plc
Condensed Consolidating Financial Statements
Net sales										0.0	0.0	0.0
Cost of sales										0.0	0.0	0.0
Gross profit										0.0	0.0	0.0
Selling, general and administrative expenses										116.3	37.7	5.2
Research and development expenses										0.0	0.0	0.0
Separation costs											2.5	3.2
Restructuring charges, net										9.8	35.3	0.0
Non-restructuring impairment charges											0.0
Gain on divestiture and license										0.0	0.0	0.0
Operating income (loss)										(126.1)	(75.5)	(8.4)
Interest expense										(96.4)	0.0	0.0
Interest income										0.0	0.0	0.0
Other income (expense), net										216.3	30.9	0.2
Intercompany interest and fees										(14.7)	(9.0)	(9.5)
Equity in net income of subsidiaries										330.6	(264.8)	76.4
Income (loss) from continuing operations before income taxes										309.7	(318.4)	58.7
Income Tax Expense (Benefit)										(15.9)	0.0	(0.3)
Income (loss) from continuing operations										325.6	(318.4)	59.0
Income (loss) from discontinued operations, net of income taxes										(0.9)	(0.9)	(0.2)
Net income (loss)										324.7	(319.3)	58.8
Other comprehensive loss, net of tax										(64.8)	(42.8)	28.4
Comprehensive income (loss)										259.9	(362.1)	87.2
Mallinckrodt International Finance S.A.
Condensed Consolidating Financial Statements
Net sales										0.0	0.0	0.0
Cost of sales										0.0	0.0	0.0
Gross profit										0.0	0.0	0.0
Selling, general and administrative expenses										15.7	7.3	0.1
Research and development expenses										0.0	0.0	0.0
Separation costs											0.0	0.6
Restructuring charges, net										0.0	0.0	0.0
Non-restructuring impairment charges											0.0
Gain on divestiture and license										0.0	0.0	0.0
Operating income (loss)										(15.7)	(7.3)	(0.7)
Interest expense										(230.2)	(86.3)	(19.6)
Interest income										0.1	0.0	0.0
Other income (expense), net										0.0	0.0	0.0
Intercompany interest and fees										0.0	0.0	0.0
Equity in net income of subsidiaries										496.3	(171.2)	96.7
Income (loss) from continuing operations before income taxes										250.5	(264.8)	76.4
Income Tax Expense (Benefit)										0.0	0.0	0.0
Income (loss) from continuing operations										250.5	(264.8)	76.4
Income (loss) from discontinued operations, net of income taxes										0.0	0.0	0.0
Net income (loss)										250.5	(264.8)	76.4
Other comprehensive loss, net of tax										(64.8)	(42.8)	28.4
Comprehensive income (loss)										185.7	(307.6)	104.8
Other Subsidiaries
Condensed Consolidating Financial Statements
Net sales										3,346.9	2,082.0	1,712.3
Cost of sales										1,493.3	1,021.8	890.0
Gross profit										1,853.6	1,060.2	822.3
Selling, general and administrative expenses										1,037.8	700.0	490.6
Research and development expenses										185.1	163.5	157.9
Separation costs											7.1	70.4
Restructuring charges, net										30.6	46.1	23.7
Non-restructuring impairment charges											151.6
Gain on divestiture and license										(3.5)	(15.0)	(2.9)
Operating income (loss)										603.6	6.9	82.6
Interest expense										(25.2)	0.0	0.1
Interest income										97.1	5.2	0.3
Other income (expense), net										(208.2)	(27.8)	1.2
Intercompany interest and fees										14.7	9.0	9.5
Equity in net income of subsidiaries										250.5	(300.2)	0.0
Income (loss) from continuing operations before income taxes										732.5	(306.9)	93.7
Income Tax Expense (Benefit)										(77.0)	(10.1)	47.8
Income (loss) from continuing operations										809.5	(296.8)	45.9
Income (loss) from discontinued operations, net of income taxes										17.4	(174.6)	50.8
Net income (loss)										826.9	(471.4)	96.7
Other comprehensive loss, net of tax										(69.9)	(84.1)	35.7
Comprehensive income (loss)										757.0	(555.5)	132.4
Eliminations
Condensed Consolidating Financial Statements
Net sales										0.0	0.0	0.0
Cost of sales										0.0	0.0	0.0
Gross profit										0.0	0.0	0.0
Selling, general and administrative expenses										0.0	0.0	0.0
Research and development expenses										0.0	0.0	0.0
Separation costs											0.0	0.0
Restructuring charges, net										0.0	0.0	0.0
Non-restructuring impairment charges											0.0
Gain on divestiture and license										0.0	0.0	0.0
Operating income (loss)										0.0	0.0	0.0
Interest expense										96.2	3.7	0.0
Interest income										(96.2)	(3.7)	0.0
Other income (expense), net										0.0	0.0	0.0
Intercompany interest and fees										0.0	0.0	0.0
Equity in net income of subsidiaries										(1,077.4)	736.2	(173.1)
Income (loss) from continuing operations before income taxes										(1,077.4)	736.2	(173.1)
Income Tax Expense (Benefit)										0.0	0.0	0.0
Income (loss) from continuing operations										(1,077.4)	736.2	(173.1)
Income (loss) from discontinued operations, net of income taxes										0.0	0.0	0.0
Net income (loss)										(1,077.4)	736.2	(173.1)
Other comprehensive loss, net of tax										134.7	126.9	(64.1)
Comprehensive income (loss)										$ (942.7)	$ 863.1	$ (237.2)

[1] Domestic reflects U.K. in fiscal 2015, and U.S. federal and state in fiscal 2014 and fiscal 2013.