Accumulated other comprehensive income (loss) (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019 USD ($)
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Beginning balance	$ 7,440,059
Ending balance	7,577,045
Foreign currency translation adjustments
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Beginning balance	(782,102)
Current period other comprehensive income	13,953
Ending balance	(768,149)
Pensions, net of tax
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Beginning balance	(9,506)
Current period other comprehensive income	108
Ending balance	(9,398)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Beginning balance	(791,608)
Current period other comprehensive income	14,061
Ending balance	$ (777,547)