Accumulated other comprehensive income (loss) (Details) $ in Thousands	3 Months Ended
	Apr. 02, 2016 USD ($)
Accumulated Other Comprehensive Income Rollforward [Roll Forward]
Balance as of December 31, 2015	$ 4,860,863
Balance as of April 2, 2016	5,156,578
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	120,768
Balance as of April 2, 2016	(667,884)
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	(20)
Balance as of April 2, 2016	(4,936)
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	120,748
Balance as of April 2, 2016	$ (672,820)