Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 27, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018	Dec. 28, 2018	Sep. 26, 2014
Income Taxes [Line Items]
Income tax benefit	$ 27.6	$ 122.9	$ 256.6	$ 203.9
Increase (decrease) tax benefit	95.3		(52.7)
Increase (Decrease) Tax Benefit, Intercompany Financing Reorganization	(92.5)		97.2
Loss (income) from continuing operations before income taxes	$ 28.5	$ 8.7	$ 102.8	$ 107.4
Effective tax rate	96.80%	1412.60%	249.60%	189.90%
Current Income Tax Expense	$ 3.3	$ 8.5	$ 47.4	$ 29.8
Deferred Income Tax Benefit	(30.9)	$ (131.4)	(304.0)	$ (233.7)
Deferred Tax Liabilities Installment Sales	0.0		0.0		$ 227.5
Income Taxes Paid, Net			30.1		12.4
Operating Loss Carryforwards	849.3		849.3
Operating Loss Carryforward, Measured at Applicable Statutory Tax Rates	178.4		178.4
Unrecognized tax benefits	439.4		439.4		287.7
Unrecognized tax benefits, net increase			151.7
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions			152.3
Unrecognized tax benefits, net increase related to prior period tax positions			13.5
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities			1.0
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations			13.1
Unrecognized tax benefits, which if favorably settled would benefit the effective tax rate	429.9		429.9
Interest accrued on unrecognized tax benefits	43.4		43.4		$ 37.1
Unrecognized tax benefits that would impact effective tax rate, upper bound of change	111.2		111.2
Income tax penalties and interest accrued that would impact effective tax rate, upper bound of change	33.3		33.3
Increase (Decrease) Tax Expense (Benefit), Change in Operating Income	(18.6)		(41.8)
Increase Tax Benefit, Prior Period Adjustment	9.3
Increase (Decrease), Tax Expense (Benefit), Gain on Debt Repurchases			(10.1)
Increase (Decrease), Tax Expense (Benefit), Restructuring			(11.2)
Increase (Decrease), Tax Expense (Benefit), Non-restructuring Impairment Charge			8.5
Increase (Decrease), Tax Expense (Benefit), Separation Costs	6.5		10.1
Increase (Decreased) Deferred Tax Asset, Change in Statutory Tax Rate			(65.8)
Discontinued Operations [Member]
Income Taxes [Line Items]
Unrecognized tax benefits, which if favorably settled would benefit the effective tax rate	$ 20.0		20.0
Intercompany Financing and Legal Entity Ownership Reorganization [Member]
Income Taxes [Line Items]
Increase (Decrease) in Deferred Tax Liabilities, Other			26.4
Increase (Decrease) Deferred Tax Asset, Tax Loss and Credit Carryforwards			(20.8)
Current Income Tax Expense			28.9
Deferred Income Tax Benefit			(215.7)
Increase (decrease), deferred tax assets, excess interest carryforwrds			$ 35.4
Luxembourg [Member]
Income Taxes [Line Items]
Effective tax rate			24.90%		26.00%
Internal Revenue Service (IRS) [Member] | Cadence Pharmaceuticals, Inc. [Member]
Income Taxes [Line Items]
Proposed Adjustment to Taxable Income						$ 871.0