Commitments and Contingencies (Narrative) (Details)				3 Months Ended							6 Months Ended				12 Months Ended
	Jun. 26, 2020 USD ($) Case	Feb. 25, 2020 USD ($) $ / shares	Mar. 19, 2014 USD ($)	Jun. 26, 2020 USD ($) Case		Jun. 14, 2020 USD ($)	Mar. 27, 2020 USD ($)	Sep. 27, 2019 USD ($)	Jun. 28, 2019 USD ($)	Dec. 26, 2014 USD ($)	Jun. 26, 2020 USD ($) lawsuit Case		Jun. 14, 2020 USD ($)	Jun. 28, 2019 USD ($)	Dec. 27, 2019 USD ($)	Apr. 07, 2020
Loss Contingencies [Line Items]
Environmental liabilities	$ 61,600,000			$ 61,600,000							$ 61,600,000
Interest Payable, Installment Sales	36,600,000			36,600,000							36,600,000				$ 47,400,000
Operating Loss Carryforwards	$ 891,300,000			891,300,000							891,300,000
Decrease, Interest Payable, Installment Sales											10,800,000
Medicaid lawsuit (Note 11)				639,700,000
Sales [Member]
Loss Contingencies [Line Items]
Medicaid lawsuit (Note 11)				534,400,000	[1],[2]				$ 0		$ 534,400,000	[1],[2]		$ 0
Operating Expenses
Loss Contingencies [Line Items]
Medicaid lawsuit (Note 11)				$ 105,300,000
Asbestos Matters
Loss Contingencies [Line Items]
Pending claims | Case	11,800			11,800							11,800
Estimation of liability, historical term											5 years
Estimation of liability, expected future term of claims											7 years
Marietta, GA Litigation [Member]
Loss Contingencies [Line Items]
Proceeds from Customers															2,000,000.0
Accrued and other current liabilities
Loss Contingencies [Line Items]
Environmental liabilities, current	$ 1,300,000			$ 1,300,000							$ 1,300,000
Minimum | Environmental Remediation
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	38,000,000.0			38,000,000.0							38,000,000.0
Maximum | Environmental Remediation
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	86,900,000			86,900,000							86,900,000
Questcor Subpoena [Member]
Loss Contingencies [Line Items]
Payments for Legal Settlements								$ 15,400,000
Boston Civil Investigative Demand [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	0.0			0.0							0.0
Boston Civil Investigative Demand [Member] | Maximum
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	1,280,000,000.0			1,280,000,000.0							1,280,000,000.0
Medicaid Lawsuit [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	0.0			0.0							0.0
Decrease in revenue	8,600,000					$ 12,300,000							$ 27,600,000
Medicaid Lawsuit [Member] | Sales Channel, Through Intermediary [Member]
Loss Contingencies [Line Items]
Decrease in revenue	6,800,000
Track 1 Cases [Member]
Loss Contingencies [Line Items]
Payments for Legal Settlements							$ 24,000,000.0
Loss Contingency Accrual, Product Liability, Gross	6,000,000.0			6,000,000.0							6,000,000.0
Loss Contingency, Accrual, Noncurrent	500,000			500,000							$ 500,000
Opioid crisis [Member] | Cities, Counties, and/or Other Government-related Persons/Entities [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit											2,584
Opioid crisis [Member] | Hospitals, Health Systems, Unions, Health and Welfare Fund or Third-Party Payers [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit											271
Opioid crisis [Member] | Individuals [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit											119
Opioid crisis [Member] | Schools and School Boards [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit											6
Opioid crisis [Member] | State Attorney Generals [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit											17
Opioid crisis [Member] | U.S. States [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit											243
Opioid Claimant Trust [Member]
Loss Contingencies [Line Items]
Warrant, Exercise Price | $ / shares		$ 3.15
Litigation Settlement, Amount Awarded to Other Party, Settlement Closing Amount		$ 300,000,000.0
Litigation Settlement, Amount Awarded to Other Party, Post Closing Settlement Amount, Total		1,300,000,000.0
Litigation Settlement, Amount Awarded to Other Party, Post Closing Settlement Amount, Year One & Two		200,000,000.0
Litigation Settlement, Amount Awarded to Other Party, Post Closing Settlement Amount, Year Three through Eight		$ 150,000,000.0
Opioid Claimant Trust [Member] | Maximum
Loss Contingencies [Line Items]
Acquisition of Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners, Quarterly Limit		5.00%
Loss Contingency Accrual															1,600,000,000.0
Warrant Expense, Opioid-related Settlement											$ 35,100,000				$ 43,400,000
New York State Department of Financial Services [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 5,000			$ 5,000							5,000
Acthar | Humana Inc. [Member]
Loss Contingencies [Line Items]
Proceeds from Customers											$ 700,000,000.0
Cadence Pharmaceuticals, Inc. [Member]
Loss Contingencies [Line Items]
Business Combination, Consideration Transferred			$ 1,329,000,000.0
Internal Revenue Service (IRS) [Member] | Cadence Pharmaceuticals, Inc. [Member]
Loss Contingencies [Line Items]
Proposed Adjustment to Taxable Income										$ 871,000,000.0
4.88% Senior Notes
Loss Contingencies [Line Items]
Debt Instrument, Interest Rate, Stated Percentage																4.875%
Senior Notes | 5.75% Senior Notes
Loss Contingencies [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.75%			5.75%							5.75%
Senior Notes | 10.00% Second Lien Senior Notes
Loss Contingencies [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	10.00%			10.00%							10.00%
Other Ownership Interest [Member] | Opioid Claimant Trust [Member] | Maximum
Loss Contingencies [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		19.99%

[1] Of this amount, $12.3 million and $27.6 million represent the impact of the Medicaid rebate calculation through June 14, 2020 for the three and six months ended June 26, 2020, respectively.

[2] Specialty Brands net sales for the three and six months ended June 26, 2020 includes the prospective change to the Medicaid rebate calculation, which served to reduce Acthar Gel net sales by $8.6 million for the period from June 15, 2020 through June 26, 2020, of which $6.8 million represents the channel impact. Of the $534.4 million recorded as a component of net sales, $12.3 million and $27.6 million represent the impact of the Medicaid rebate calculation through June 14, 2020 for the three and six months ended June 26, 2020, respectively. See Note 11 for further detail on the status of the Medicaid lawsuit.