Accumulated other comprehensive income (loss) (Details) $ in Thousands	6 Months Ended
	Jul. 02, 2016 USD ($)
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2015	$ 4,860,863
Balance as of July 2, 2016	5,385,583
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2015	(788,652)
Current period other comprehensive income (loss) before reclassifications	77,714
Balance as of July 2, 2016	(710,938)
Pensions [Member]
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2015	(4,916)
Current period other comprehensive income (loss) before reclassifications	(7)
Balance as of July 2, 2016	(4,923)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2015	(793,568)
Current period other comprehensive income (loss) before reclassifications	77,707
Balance as of July 2, 2016	$ (715,861)