Pension Benefits - Changes in Benefit Obligation and Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Change in benefit obligation
Benefit obligation at beginning of year	$ 1,881,790	$ 2,039,051
Service cost	10,065	9,799	$ 9,134
Interest cost	60,153	68,582	74,465
Plan participants’ contributions	3	9
Actuarial (gain)/loss	(133,891)	158,322
Curtailments	(200)	0
Settlements	0	(269,287)
Benefits paid	(103,398)	(124,838)
Effects of change in currency conversion	(58)	152
Benefit obligation at end of year	1,714,464	1,881,790	2,039,051
Change in plan assets
Fair value of plan assets at beginning of year	1,567,411	1,576,760
Actual return on plan assets	(81,529)	238,622
Employer contributions	27,664	146,145
Plan participants’ contributions	3	9
Settlements	0	(269,287)
Benefits paid	(103,398)	(124,838)
Fair value of plan assets at end of year	1,410,151	1,567,411	1,576,760
Amount recognized in the Consolidated Balance Sheets
Current liabilities	(17,034)	(16,901)
Noncurrent liabilities	(287,279)	(297,478)
Net amount recognized	(304,313)	(314,379)
Amount recognized in accumulated other comprehensive loss
Actuarial loss	748,702	751,074
Prior service credit	(18,786)	(20,731)
Total	729,916	730,343
Qualified Plan [Member]
Change in benefit obligation
Benefit obligation at beginning of year	1,636,488	1,798,652
Service cost	9,986	9,720	8,991
Interest cost	52,770	60,742	66,293
Plan participants’ contributions	3	9
Actuarial (gain)/loss	(123,670)	142,980
Curtailments	0	0
Settlements	0	(269,287)
Benefits paid	(84,179)	(106,328)
Effects of change in currency conversion	0	0
Benefit obligation at end of year	1,491,398	1,636,488	1,798,652
Change in plan assets
Fair value of plan assets at beginning of year	1,567,411	1,576,760
Actual return on plan assets	(81,529)	238,622
Employer contributions	8,445	127,635
Plan participants’ contributions	3	9
Settlements	0	(269,287)
Benefits paid	(84,179)	(106,328)
Fair value of plan assets at end of year	1,410,151	1,567,411	1,576,760
Amount recognized in the Consolidated Balance Sheets
Current liabilities	0	0
Noncurrent liabilities	(81,247)	(69,077)
Net amount recognized	(81,247)	(69,077)
Amount recognized in accumulated other comprehensive loss
Actuarial loss	654,579	641,194
Prior service credit	(18,786)	(20,731)
Total	635,793	620,463
Nonqualified Plan [Member]
Change in benefit obligation
Benefit obligation at beginning of year	245,302	240,399
Service cost	79	79	143
Interest cost	7,383	7,840	8,172
Plan participants’ contributions	0	0
Actuarial (gain)/loss	(10,221)	15,342
Curtailments	(200)	0
Settlements	0	0
Benefits paid	(19,219)	(18,510)
Effects of change in currency conversion	(58)	152
Benefit obligation at end of year	223,066	245,302	240,399
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	19,219	18,510
Plan participants’ contributions	0	0
Settlements	0	0
Benefits paid	(19,219)	(18,510)
Fair value of plan assets at end of year	0	0	$ 0
Amount recognized in the Consolidated Balance Sheets
Current liabilities	(17,034)	(16,901)
Noncurrent liabilities	(206,032)	(228,401)
Net amount recognized	(223,066)	(245,302)
Amount recognized in accumulated other comprehensive loss
Actuarial loss	94,123	109,880
Prior service credit	0	0
Total	$ 94,123	$ 109,880