Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 30, 2016	Dec. 25, 2015
Condensed Consolidating Financial Statements
Net sales	$ 829.9	$ 811.2
Cost of sales	384.1	360.3
Gross profit	445.8	450.9
Selling, general and administrative expenses	368.3	223.3
Research and development expenses	66.2	61.4
Restructuring charges, net	3.8	4.1
Impairment Charges, Not Related to Restructuring Activities	214.3
Non-restructuring impairment charges	214.3	0.0
Operating (loss) income	(206.8)	162.1
Interest expense	(91.3)	(97.8)
Interest income	0.5	0.2
Other income (loss), net	(0.9)	2.0
Intercompany Interest And Fees	0.0	0.0
Income (Loss) from Equity Method Investments	0.0	0.0
Income (loss) from continuing operations before income taxes	(298.5)	66.5
Income tax benefit	(121.7)	(37.3)
Income from continuing operations	(176.8)	103.8
Discontinued operation, (loss) income from discontinued operations, net of tax	23.6	107.3
Net (loss) income	(153.2)	211.1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	13.1	(66.2)
Comprehensive (loss) income	(140.1)	144.9
Mallinckrodt plc
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	13.4	10.4
Research and development expenses	0.0	0.0
Restructuring charges, net	0.0	0.0
Impairment Charges, Not Related to Restructuring Activities	0.0
Operating (loss) income	(13.4)	(10.4)
Interest expense	(2.9)	(68.0)
Interest income	0.0	0.0
Other income (loss), net	1.8	67.7
Intercompany Interest And Fees	(4.4)	(3.2)
Income (Loss) from Equity Method Investments	(136.5)	211.0
Income (loss) from continuing operations before income taxes	(155.4)	197.1
Income tax benefit	(2.2)	(14.0)
Income from continuing operations	(153.2)	211.1
Discontinued operation, (loss) income from discontinued operations, net of tax	0.0	0.0
Net (loss) income	(153.2)	211.1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	13.1	(66.2)
Comprehensive (loss) income	(140.1)	144.9
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	0.3
Research and development expenses	0.0	0.0
Restructuring charges, net	0.0	0.0
Impairment Charges, Not Related to Restructuring Activities	0.0
Operating (loss) income	(0.2)	(0.3)
Interest expense	(81.1)	(81.9)
Interest income	0.1	0.0
Other income (loss), net	0.7	1.7
Intercompany Interest And Fees	0.0	(0.1)
Income (Loss) from Equity Method Investments	35.2	312.0
Income (loss) from continuing operations before income taxes	(45.3)	231.4
Income tax benefit	(0.3)	0.0
Income from continuing operations	(45.0)	231.4
Discontinued operation, (loss) income from discontinued operations, net of tax	0.4	40.3
Net (loss) income	(44.6)	271.7
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	13.1	(66.2)
Comprehensive (loss) income	(31.5)	205.5
Other Subsidiaries
Condensed Consolidating Financial Statements
Net sales	829.9	811.2
Cost of sales	384.1	360.3
Gross profit	445.8	450.9
Selling, general and administrative expenses	354.7	212.6
Research and development expenses	66.2	61.4
Restructuring charges, net	3.8	4.1
Impairment Charges, Not Related to Restructuring Activities	214.3
Operating (loss) income	(193.2)	172.8
Interest expense	(17.9)	(21.0)
Interest income	11.0	73.3
Other income (loss), net	(3.4)	(67.4)
Intercompany Interest And Fees	4.4	3.3
Income (Loss) from Equity Method Investments	(44.5)	271.7
Income (loss) from continuing operations before income taxes	(243.6)	432.7
Income tax benefit	(119.2)	(23.3)
Income from continuing operations	(124.4)	456.0
Discontinued operation, (loss) income from discontinued operations, net of tax	23.2	67.0
Net (loss) income	(101.2)	523.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	26.0	(132.5)
Comprehensive (loss) income	(75.2)	390.5
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
Impairment Charges, Not Related to Restructuring Activities	0.0
Operating (loss) income	0.0	0.0
Interest expense	10.6	73.1
Interest income	(10.6)	(73.1)
Other income (loss), net	0.0	0.0
Intercompany Interest And Fees	0.0	0.0
Income (Loss) from Equity Method Investments	145.8	(794.7)
Income (loss) from continuing operations before income taxes	145.8	(794.7)
Income tax benefit	0.0	0.0
Income from continuing operations	145.8	(794.7)
Discontinued operation, (loss) income from discontinued operations, net of tax	0.0	0.0
Net (loss) income	145.8	(794.7)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(39.1)	198.7
Comprehensive (loss) income	$ 106.7	$ (596.0)