Accumulated other comprehensive income (loss) (Details) $ in Thousands	9 Months Ended
	Sep. 29, 2018 USD ($)
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2017	$ 7,067,009
Balance as of September 29, 2018	7,571,777
Foreign currency translation adjustments
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2017	(547,927)
Current period other comprehensive income	(146,143)
Balance as of September 29, 2018	(694,070)
Pensions, net of tax
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2017	(10,600)
Current period other comprehensive income	291
Balance as of September 29, 2018	(10,309)
AOCI attributable to parent
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2017	(558,527)
Current period other comprehensive income	(145,852)
Balance as of September 29, 2018	$ (704,379)