Commitments and Contingencies (Narrative) (Details)				3 Months Ended					9 Months Ended		12 Months Ended
	Oct. 12, 2020 USD ($)	Feb. 25, 2020 USD ($) $ / shares	Mar. 19, 2014 USD ($)	Sep. 25, 2020 USD ($) Case	Jun. 26, 2020 USD ($)	Mar. 27, 2020 USD ($)	Dec. 27, 2019 USD ($)	Sep. 27, 2019 USD ($)	Sep. 25, 2020 USD ($) Case lawsuit	Sep. 27, 2019 USD ($)	Dec. 27, 2019 USD ($)	Oct. 11, 2020 USD ($)	Apr. 07, 2020
Loss Contingencies [Line Items]
Environmental liabilities				$ 61,300,000					$ 61,300,000
Interest Payable, Installment Sales				28,200,000			$ 47,400,000		28,200,000		$ 47,400,000
Decrease, Interest Payable, Installment Sales									19,200,000
Medicaid lawsuit (Note 11)									640,200,000
Sales [Member]
Loss Contingencies [Line Items]
Medicaid lawsuit (Note 11)				$ 700,000				$ 0	535,100,000	$ 0
Operating Expenses
Loss Contingencies [Line Items]
Medicaid lawsuit (Note 11)									$ 105,100,000
Asbestos Matters
Loss Contingencies [Line Items]
Pending claims | Case				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
Minimum | Environmental Remediation
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss				37,800,000					37,800,000
Maximum | Environmental Remediation
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss				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
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
Medicaid Lawsuit [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual				0.0					0.0
Decrease in revenue				22,200,000					30,800,000
Medicaid Lawsuit [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount Awarded to Other Party, Post Closing Settlement Amount, Total	$ 260,000,000.0
Medicaid Lawsuit [Member] | Maximum | Subsequent Event [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss												$ 640,000,000
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
Loss Contingency, Accrual, Noncurrent				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									2,618
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									270
Opioid crisis [Member] | Individuals [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit									128
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									247
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				1,600,000,000.0
Warrant Expense, Opioid-related Settlement									$ 9,300,000		$ 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
Humana Inc. [Member] | Acthar
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
Increase (Decrease), Taxable Income									356,500,000
Income Tax Examination, Penalties and Interest Expense									$ 11,800,000
4.88% Senior Notes
Loss Contingencies [Line Items]
Debt Instrument, Interest Rate, Stated Percentage													4.875%
Other Ownership Interest [Member] | Opioid Claimant Trust [Member] | Maximum
Loss Contingencies [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		19.99%