Debt and Credit Facilities (Narrative) (Details) $ / shares in Units, shares in Millions				3 Months Ended	6 Months Ended
	May 21, 2020 USD ($) Trading_day $ / shares shares	May 06, 2020 USD ($)	Sep. 20, 2019 USD ($)	Jul. 03, 2020 USD ($) $ / shares	Jul. 03, 2020 USD ($) $ / shares	Jun. 28, 2019 USD ($)	Jul. 03, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Sep. 20, 2019 EUR (€)
Debt Instrument [Line Items]
Unamortized debt issuance costs				$ 120,000,000	$ 120,000,000
Total borrowings under term loan			$ 1,300,000,000
Senior unsecured revolving credit facility			$ 250,000,000
Payments of debt restructuring		$ 3,000,000
Deferred debt restructuring costs		$ 2,000,000
Proceeds from convertible debt					517,500,000	$ 0
Long-term debt				1,975,700,000	1,975,700,000			$ 1,324,900,000
US term loan due 2022
Debt Instrument [Line Items]
Debt instrument, term			3 years
Term loan			$ 650,000,000	$ 650,000,000	$ 650,000,000
Loan facility interest rates				3.70%	3.40%
Long-term debt			$ 650,000,000	$ 647,700,000	$ 647,700,000			648,700,000
Debt issuance costs				$ 2,300,000	$ 2,300,000			1,300,000
Euro term loan due 2022
Debt Instrument [Line Items]
Debt instrument, term			3 years
Term loan | €							€ 600,000,000		€ 600,000,000
Loan facility interest rates				2.50%	1.80%
Long-term debt				$ 673,200,000	$ 673,200,000			672,000,000.0
Debt issuance costs				1,700,000	1,700,000			900,000
Senior multi-currency revolving credit facility ($250.0 million borrowing capacity) (the “Revolving Credit Facility”)
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity				250,000,000	250,000,000
Revolving credit facility increase				$ 200,000,000	$ 200,000,000
Loan facility interest rates				3.10%	3.00%
Senior multi-currency revolving credit facility ($250.0 million borrowing capacity) (the “Revolving Credit Facility”) | Standby letters of credit
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity				$ 20,000,000	$ 20,000,000
Convertible Debt | 2.375% Convertible Senior Notes Over Allotment Option
Debt Instrument [Line Items]
Term loan	$ 68,000,000
Convertible Debt | Convertible senior notes, net of deferred debt issuance costs of $11.7 million and unamortized discount of $104.6 million
Debt Instrument [Line Items]
Term loan	518,000,000
Debt issuance costs	3,000,000
Proceeds from convertible debt	$ 503,000,000
Interest rate	2.375%
Conversion ratio	0.0475862
Conversion price (in USD per share) | $ / shares	$ 21.01			$ 23.79	$ 23.79
Repurchase price (as a percentage of principal)	100.00%
Percentage stock price trigger	130.00%
Threshold of trading days | Trading_day	20
Threshold of consecutive trading days | Trading_day	30
Long-term debt	$ 411,000,000			$ 401,200,000	$ 401,200,000			$ 0
Fair value of convertible debt				644,000,000	644,000,000
Equity component	107,000,000
Debt issuance costs	12,000,000			$ 11,700,000	$ 11,700,000
Net deferred tax liability	$ 20,000,000
Effective interest rate				7.30%	7.30%		7.30%
If-converted value in excess of principal					$ 9,000,000
Convertible Debt | 2.375% Convertible Senior Notes, Capped Calls
Debt Instrument [Line Items]
Conversion price (in USD per share) | $ / shares	$ 23.79
Convertible note hedge, price per common share (in USD per share) | $ / shares	$ 21.01
Convertible note hedge (in shares) | shares	2.9
Convertible note hedge	$ 21,000,000
Line of Credit | Senior multi-currency revolving credit facility ($250.0 million borrowing capacity) (the “Revolving Credit Facility”)
Debt Instrument [Line Items]
Debt instrument, term			5 years