Income Taxes (Narrative) (Details) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
	Jun. 16, 2022	Dec. 30, 2022	Jun. 16, 2022	Dec. 30, 2022	Dec. 31, 2021	Dec. 25, 2020
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount		$ 4.7	$ (226.5)		$ 224.9	$ 315.3
Increase (Decrease) Tax Expense (Benefit), Change in Operating Income		(30.2)	(12.8)	$ 92.9
Current Income Tax Expense (Benefit)		(27.1)	(23.9)		(46.4)	(375.3)
Increase (Decrease) Tax Benefit, Jurisdiction Rate Difference				(90.4)
Income Taxes Paid, Net		(3.0)	(3.0)		160.0	(39.9)
Deferred Tax Liabilities, Intangible Assets		0.0		0.0	108.5
Deferred Tax Assets, Other		159.8		159.8	292.2
Tax loss and credit carryforward		3,646.0		3,646.0	4,147.5
Unrecognized Tax Benefits, Interest on Income Taxes Accrued		2.8		2.8	18.9
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 24.8	24.8	24.8	24.8	77.0	85.9
Unrecognized Tax Benefits, Interest on Income Taxes Expense		(0.6)	(16.7)		(2.2)	(16.2)
Tax Credit Carryforward, Amount		1.9		1.9
Increase (Decrease) Tax Expense (Benefit) due to opioid-related settlement charge				10.6
Excess in Book over Tax Basis, Foreign Subsidiaries		3.1		3.1
Deferred Income Tax Expense (Benefit)		(24.9)	(473.4)		(59.9)	384.2
(Benefit) expense from income taxes		(52.0)	(497.3)		(106.3)	8.9
Deferred Tax Assets, Capital Loss Carryforwards		1,412.6		1,412.6	1,605.0
Increase (Decrease) Tax Benefit, Medicaid Lawsuit				48.9
Increase (Decrease) Tax Expense (Benefit) due to reorganization items, net				27.6
Valuation Allowance Tax Expense					189.7	618.2
Increase (Decrease) Valuation Allowance Tax Expense					428.5
Increase (Decrease) Valuation Allowance Tax Expense (Benefit), Operational Activity					288.9
Increase (Decrease) Valuation Allowance Tax Expense (Benefit), deferred tax assets				204.9
Increase (Decrease) Valuation Allowance Tax Expense (Benefit), tax rate changes				65.3
Increase (Decrease) Tax Expense (Benefit), Non-restructuring Impairment Charges				13.2
Deferred Tax Liabilities, Gross		(224.4)		(224.4)	(175.6)
Foreign tax provision, refundable credits						1.0
Foreign Tax Benefit, Carryback Claims						$ 281.5
Increase (Decrease) Tax (Benefit), Inventory Step-Up Amortization		19.7
Increase (Decrease) Tax Expense (Benefit), Settlement liabilities accretion expense		8.9
Increase (Decrease) Tax Expense (Benefit), Debt accretion expense		6.3
Increase (Decrease) Tax Benefit, Fresh-Start adjustments			128.9
Increase (Decrease) Tax Expense (Benefit), Gain on LSTC adjustments			103.4
Increase (Decrease) Tax Expense (Benefit), Professional & Lender Fees			18.6
Increase (Decrease) Tax Expense Benefit, Fresh-Start Accounting Revaluation of DTA	1,202.0
Increase (Decrease) Income Tax Expense (Benefit), Release of UTP	285.3
Increase (Decrease) Tax Expense (Benefit), NOL carryforward reduction	1,209.8
Increase (Decrease) Tax Expense (Benefit), Permanently nondeductible impacts	191.9
Increase (Decrease) Tax Expense (Benefit), Prepaid income taxes	54.0
Increase (Decrease) Tax Expense (Benefit), Valuation Allowances			600.8
Unrecognized Tax Benefits, Period Increase (Decrease)			$ 306.1
Increase (Decrease) Deferred Tax Assets, Opioid-Related Litigation Settlement Payments				72.8
Increase (Decrease) Deferred Tax Assets, Intangible Assets Amortization				61.5
Increase (Decrease) Deferred Tax Assets, Fresh-Start Adjustment				904.5
Deferred Income Tax Assets, Net		475.5		475.5	0.0
Deferred income taxes		(0.3)		(0.3)	(20.9)
Deferred income tax asset (liability), net		$ (475.2)		(475.2)	$ 20.9
Increase (Decrease) Deferred Tax Assets, Other				60.6
IRELAND
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		12.50%	12.50%		12.50%	12.50%
Nuclear Imaging
Income Tax Contingency [Line Items]
(Benefit) expense from income taxes					$ 5.1	$ 18.1
Non-U.K.
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	0.1	$ 61.0	$ 0.1	61.0	1.2	33.4
Deferred Tax Assets, Operating Loss Carryforwards		3,600.6		3,600.6
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration		1,532.4		1,532.4
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration		2,068.2		2,068.2
Deferred Tax Assets, Capital Loss Carryforwards		8.7		8.7
Ireland
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	4.1	7.9	4.1	7.9	2.2	$ 0.2
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration		43.5		43.5
Deferred Tax Assets, Capital Loss Carryforwards		$ 969.5		$ 969.5
CARES Act
Income Tax Contingency [Line Items]
Proceeds from Income Tax Refunds					178.8
Operational activity
Income Tax Contingency [Line Items]
Income Taxes Paid, Net					$ (18.8)
Chapter 11 Emergence
Income Tax Contingency [Line Items]
(Benefit) expense from income taxes	$ 31.6
Alleviation of Going Concern Substantial Doubt
Income Tax Contingency [Line Items]
Increase (Decrease) Tax Expense (Benefit), Valuation Allowances			512.1
Rate differential between domestic and international jurisdictions
Income Tax Contingency [Line Items]
Increase (Decrease) Tax Expense (Benefit), Valuation Allowances			$ 88.7