Supplemental Equity Information - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 28, 2015	Jun. 30, 2016	Jun. 28, 2015
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ 2,456,744	$ 3,489,273
Other comprehensive income (loss), net of tax	$ (7,974)	$ 24,014	(7,594)	16,180
Ending Balance	2,434,186	3,627,312	2,434,186	3,627,312
Retirement Plans
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(115,334)	(1,147,769)	(116,496)	(1,172,245)
Other comprehensive loss before reclassifications	0	(18,349)	0	(3,518)
Amounts reclassified from AOCL	1,480	9,660	2,642	19,305
Other comprehensive income (loss), net of tax	1,480	(8,689)	2,642	15,787
Ending Balance	(113,854)	(1,156,458)	(113,854)	(1,156,458)
Foreign Currency Translation
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(19,494)	364,369	(20,129)	391,113
Other comprehensive loss before reclassifications	(3,788)	29,343	(3,153)	2,599
Amounts reclassified from AOCL	0	0	0	0
Other comprehensive income (loss), net of tax	(3,788)	29,343	(3,153)	2,599
Ending Balance	(23,282)	393,712	(23,282)	393,712
Other
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	3,691	2,363	5,674	2,363
Other comprehensive loss before reclassifications	(2,292)	0	(4,275)	0
Amounts reclassified from AOCL	0	0	0	0
Other comprehensive income (loss), net of tax	(2,292)	0	(4,275)	0
Ending Balance	1,399	2,363	1,399	2,363
Total
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(131,137)	(781,037)	(130,951)	(778,769)
Other comprehensive loss before reclassifications	(6,080)	10,994	(7,428)	(919)
Amounts reclassified from AOCL	1,480	9,660	2,642	19,305
Other comprehensive income (loss), net of tax	(4,600)	20,654	(4,786)	18,386
Ending Balance	$ (135,737)	$ (760,383)	$ (135,737)	$ (760,383)