Restructuring and Related Charges (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended		11 Months Ended	12 Months Ended
	Dec. 29, 2023	Dec. 30, 2022	Jun. 16, 2022	Nov. 14, 2023	Dec. 31, 2021	Dec. 01, 2021	Feb. 01, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net	$ 0.0	$ 11.1	$ 9.6	$ 0.9	$ 26.9
2018 Program | Minimum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range							$ 100.0
2018 Program | Maximum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range							$ 125.0
Restructuring Fiscal 2021 Plan | Minimum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range						$ 50.0
Restructuring Fiscal 2021 Plan | Maximum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range						$ 100.0