Earnings (Loss) per Share Schedule of Earnings per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 27, 2019		Sep. 27, 2019		Jun. 28, 2019		Mar. 29, 2019		Dec. 28, 2018		Sep. 28, 2018		Jun. 29, 2018		Mar. 30, 2018		Dec. 27, 2019	Dec. 28, 2018	Dec. 29, 2017
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ (1,161.0)	[1]	$ (0.9)	[1]	$ (0.5)	[1]	$ 155.2	[1]	$ (3,718.4)	[2],[3]	$ 114.2	[2],[3]	$ 3.2	[2],[3]	$ (20.9)	[2],[3]	$ (1,007.2)	$ (3,621.9)	$ 1,771.2
Income (loss) from discontinued operations, net of income taxes	$ 3.9		$ (0.2)		$ 7.3		$ (0.3)		$ 0.0		$ (0.4)		$ 12.4		$ 2.9		$ 10.7	$ 14.9	$ 363.2
Weighted Average Number of Shares Outstanding, Basic																	83.9	84.0	97.7
Weighted Average Number of Shares Outstanding, Diluted																	0.0	0.0	0.2
Weighted Average Number of Shares Outstanding, Diluted																	83.9	84.0	97.9
Income (Loss) from Continuing Operations, Per Basic Share	$ (13.80)	[4]	$ (0.01)	[4]	$ (0.01)	[4]	$ 1.86	[4]	$ (44.64)	[4]	$ 1.37	[4]	$ 0.04	[4]	$ (0.24)	[4]	$ (12.00)	$ (43.12)	$ 18.13
Income (Loss) from Discontinued Operations, Per Basic Share																	0.13	0.18	3.72
Earnings Per Share, Basic																	(11.88)	(42.94)	21.85
(Loss) income from continuing operations	$ (13.80)	[4]	$ (0.01)	[4]	$ (0.01)	[4]	$ 1.83	[4]	$ (44.64)	[4]	$ 1.34	[4]	$ 0.04	[4]	$ (0.24)	[4]	(12.00)	(43.12)	18.09
Income (Loss) from Discontinued Operations, Per Diluted Share																	0.13	0.18	3.71
Earnings Per Share, Diluted																	$ (11.88)	$ (42.94)	$ 21.80

[1] Includes administration expenses and certain compensation, legal, environmental and other costs not charged to the Company's reportable segments.

[2] Loss from continuing operations for the quarter ended December 28, 2018 reflects impairment charges for goodwill and an IPR&D asset. See Note 13 for further information.

[3] The "Specialty Generics Disposal Group" was included within discontinued operations during the first three quarters of fiscal 2018, and was subsequently recast to be included within continuing operations during the fourth quarter of fiscal 2018. In accordance with U.S. GAAP, depreciation and amortization are not recorded during the period in which a disposal group is classified as held-for-sale, thus the Company's financial results during the first three quarters of fiscal 2018 did not include $17.7 million and $6.8 million of depreciation and amortization expense, respectively, related to the Specialty Generics Disposal Group. During the fourth quarter of fiscal 2018, the Specialty Generics Disposal Group was reclassified to held and used and measured at its carrying amount before it was classified as held-for-sale, adjusted for depreciation and amortization expense that would have been recognized had the disposal group been continuously classified as held and used. The total adjustment of $24.5 million was reflected in loss from continuing operations during the fourth quarter of fiscal 2018, the period in which the held-for-sale criteria were no longer met. The Specialty Generics Disposal Group included (1) the Company's Specialty Generics business comprised of what was the Company's Specialty Generics segment in fiscal 2017, with the exception of BioVectra; (2) certain of the Company's non-promoted brands business; and (3) the Company's post-divestiture supply agreement with the acquirer of the contrast media and delivery systems ("CMDS") business.

[4] Includes restructuring-related accelerated depreciation.