Condensed Consolidated Statement of Changes in Shareholders' Equity Statement - USD ($) $ in Millions	Total	Ordinary Shares	Treasury Shares	Additional Paid-In Capital	Retained Earnings (Deficit)	Accumulated Other Comprehensive Loss
Shares, Outstanding		92,700,000	9,400,000
Beginning balance at Dec. 28, 2018	$ 2,887.3	$ 18.5	$ (1,617.4)	$ 5,528.2	$ (1,017.7)	$ (24.3)
Net (loss) income	154.9				154.9
Other Comprehensive Income (Loss), Net of Tax	1.3					1.3
Stock Issued During Period, Value, Stock Options Exercised	0.3			0.3
Vesting of restricted shares (in shares)		200,000	0
Vesting of restricted shares (in usd)	(0.4)	$ 0.1	$ (0.5)	0.0
Share-based compensation	$ 10.0			10.0
Reissuance of treasury shares (in shares)	0
Reissuance of treasury shares	$ (0.5)		(0.9)		(0.4)
Ending balance at Mar. 29, 2019	3,053.9	18.6	(1,617.0)	5,538.5	(863.7)	(22.5)
Beginning balance at Dec. 28, 2018	2,887.3	18.5	(1,617.4)	5,528.2	(1,017.7)	(24.3)
Net (loss) income					161.7
Ending balance at Jun. 28, 2019	3,075.2	$ 18.7	$ (1,617.4)	5,551.5	(857.5)	(20.1)
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2018-02 [Member]	0.0				(0.5)	0.5
Shares, Outstanding		92,900,000	9,400,000
Beginning balance at Mar. 29, 2019	3,053.9	$ 18.6	$ (1,617.0)	5,538.5	(863.7)	(22.5)
Net (loss) income	6.8				6.8
Other Comprehensive Income (Loss), Net of Tax	2.4					2.4
Stock Issued During Period, Value, Stock Options Exercised	0.2			0.2
Vesting of restricted shares (in shares)		400,000	100,000
Vesting of restricted shares (in usd)	(1.9)	$ 0.1	$ (2.0)	0.0
Share-based compensation	$ 12.8			12.8
Reissuance of treasury shares (in shares)	(100,000)
Reissuance of treasury shares	$ (1.0)		(1.6)		(0.6)
Ending balance at Jun. 28, 2019	$ 3,075.2	$ 18.7	$ (1,617.4)	5,551.5	(857.5)	(20.1)
Shares, Outstanding		93,300,000	9,400,000
Shares, Outstanding		93,500,000	9,400,000
Beginning balance, ordinary shares (in shares) at Dec. 27, 2019	93,459,206
Beginning balance, treasury shares (in shares) at Dec. 27, 2019	9,353,420
Beginning balance at Dec. 27, 2019	$ 1,940.7	$ 18.7	$ (1,615.7)	5,562.5	(2,016.9)	(7.9)
Net (loss) income	(50.2)				(50.2)
Other Comprehensive Income (Loss), Net of Tax	(1.3)					(1.3)
Vesting of restricted shares (in shares)		100,000	0
Vesting of restricted shares (in usd)	(0.1)	$ 0.0	$ 0.0	(0.1)
Share-based compensation	6.7			6.7
Ending balance at Mar. 27, 2020	$ 1,895.8	18.7	(1,615.7)	5,569.1	(2,067.1)	(9.2)
Beginning balance, ordinary shares (in shares) at Dec. 27, 2019	93,459,206
Beginning balance, treasury shares (in shares) at Dec. 27, 2019	9,353,420
Beginning balance at Dec. 27, 2019	$ 1,940.7	18.7	(1,615.7)	5,562.5	(2,016.9)	(7.9)
Net (loss) income	$ (983.3)				(983.3)
Ending balance, ordinary shares (in shares) at Jun. 26, 2020	94,059,693
Ending balance, treasury shares (in shares) at Jun. 26, 2020	9,495,287
Ending balance at Jun. 26, 2020	$ 969.5	$ 18.8	$ (1,616.0)	5,575.7	(3,000.2)	(8.8)
Shares, Outstanding		93,600,000	9,400,000
Beginning balance at Mar. 27, 2020	1,895.8	$ 18.7	$ (1,615.7)	5,569.1	(2,067.1)	(9.2)
Net (loss) income	(933.1)				(933.1)
Other Comprehensive Income (Loss), Net of Tax	0.4					0.4
Vesting of restricted shares (in shares)		500,000	100,000
Vesting of restricted shares (in usd)	(0.2)	$ 0.1	$ (0.3)	0.0
Share-based compensation	$ 6.6			6.6
Ending balance, ordinary shares (in shares) at Jun. 26, 2020	94,059,693
Ending balance, treasury shares (in shares) at Jun. 26, 2020	9,495,287
Ending balance at Jun. 26, 2020	$ 969.5	$ 18.8	$ (1,616.0)	$ 5,575.7	$ (3,000.2)	$ (8.8)
Shares, Outstanding		94,100,000	9,500,000