Supplemental Equity Information (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (781,037)	$ (467,196)	$ (778,769)	$ (494,055)
Other comprehensive income (loss) before reclassifications	10,994	1,766	(919)	21,523
Amounts reclassified from accumulated other comprehensive income	9,660	6,888	19,305	13,990
Other comprehensive income (loss)	20,654	8,654	18,386	35,513
Ending Balance	(760,383)	(458,542)	(760,383)	(458,542)
Retirement Plans
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,145,406)	(899,026)	(1,169,882)	(921,232)
Other comprehensive income (loss) before reclassifications	(18,349)	(11,042)	(3,518)	4,062
Amounts reclassified from accumulated other comprehensive income	9,660	6,888	19,305	13,990
Other comprehensive income (loss)	(8,689)	(4,154)	15,787	18,052
Ending Balance	(1,154,095)	(903,180)	(1,154,095)	(903,180)
Foreign Currency Translation
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	364,369	431,830	391,113	427,177
Other comprehensive income (loss) before reclassifications	29,343	12,808	2,599	17,461
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other comprehensive income (loss)	29,343	12,808	2,599	17,461
Ending Balance	$ 393,712	$ 444,638	$ 393,712	$ 444,638