Liabilities Subject to Compromise (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 26, 2021	Dec. 25, 2020
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		$ 5,914.2	$ 4,192.6
Lease rejection
Schedule of Liabilities Subject to Compromise [Line Items]
Increase (Decrease) Other current and non-current liabilities		34.8
Contingent Consideration
Schedule of Liabilities Subject to Compromise [Line Items]
Increase (Decrease) Other current and non-current liabilities		15.6
Accounts Payable
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		52.9	61.9
Interest Payable, Current
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		35.2	35.2
Long-term Debt
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise	[1]	3,446.5	1,660.7
Long-term Debt | Term Loans due Sept 2024 and Feb 2025
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		1,785.8
Medicaid Lawsuit [Member]
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		638.9	638.9
Opioid-related litigation settlement liability
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		1,600.0	1,600.0
Other current and non-current liabilities
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		108.1	163.5
Liability, Defined Benefit Plan, Noncurrent
Schedule of Liabilities Subject to Compromise [Line Items]
Liabilities Subject to Compromise		$ 32.6	$ 32.4

[1] In connection with the Company’s Chapter 11 Cases, $3,446.5 million and $1,660.7 million outstanding secured and unsecured debt instruments have been reclassified to LSTC in the Company's unaudited condensed consolidated balance sheets as of March 26, 2021 and December 25, 2020, respectively. Up to the date of reclassification to LSTC, the Company continued to accrue interest expense in relation to these debt instruments reclassified to LSTC. Refer to Note 2 for further information