Condensed Consolidated Statement of Changes in Shareholders' Equity Statement - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Ordinary Shares	Treasury Shares	Additional Paid-In Capital	Retained Earnings (Deficit)	Retained Earnings (Deficit) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment
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)
Beginning balance (Accounting Standards Update 2018-02 [Member]) at Dec. 28, 2018		$ 0.0					$ (0.5)		$ 0.5
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)
Beginning balance (Accounting Standards Update 2018-02 [Member]) at Dec. 28, 2018		$ 0.0					$ (0.5)		$ 0.5
Net (loss) income						160.6
Ending balance at Sep. 27, 2019	3,080.4		$ 18.7	$ (1,615.6)	5,559.2	(859.8)		(22.1)
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
Net (loss) income	(1.1)					(1.1)
Other Comprehensive Income (Loss), Net of Tax	(2.0)							(2.0)
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	$ 7.8				7.8
Reissuance of treasury shares (in shares)	(100,000)
Reissuance of treasury shares	$ (0.6)			(1.8)		(1.2)
Ending balance at Sep. 27, 2019	$ 3,080.4		$ 18.7	$ (1,615.6)	5,559.2	(859.8)		(22.1)
Shares, Outstanding			93,400,000	9,300,000
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	$ (791.7)					(791.7)
Ending balance, ordinary shares (in shares) at Sep. 25, 2020	94,104,519
Ending balance, treasury shares (in shares) at Sep. 25, 2020	9,506,022
Ending balance at Sep. 25, 2020	$ 1,165.7		$ 18.8	$ (1,616.1)	5,580.0	(2,808.6)		(8.4)
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 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
Net (loss) income	191.6					191.6
Other Comprehensive Income (Loss), Net of Tax	0.4							0.4
Vesting of restricted shares (in shares)			0	0
Vesting of restricted shares (in usd)	(0.1)		$ 0.0	$ (0.1)	0.0
Share-based compensation	$ 4.3				4.3
Ending balance, ordinary shares (in shares) at Sep. 25, 2020	94,104,519
Ending balance, treasury shares (in shares) at Sep. 25, 2020	9,506,022
Ending balance at Sep. 25, 2020	$ 1,165.7		$ 18.8	$ (1,616.1)	$ 5,580.0	$ (2,808.6)		$ (8.4)
Shares, Outstanding			94,100,000	9,500,000