Pension Benefits - Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Details) (USD $)	12 Months Ended
	Dec. 30, 2012	Dec. 25, 2011	Dec. 26, 2010	Jan. 01, 2010
Pension Benefits
Defined contribution plan, cost recognized	$ 18,000,000	$ 23,000,000	$ 23,000,000
Incremental employer contribution percentage based on employee's eligible earnings				3.00%
Pension Plans, Defined Benefit [Member]
Pension Benefits
Net actuarial loss	(98,468,000)	(255,907,000)	(122,879,000)
Prior service credit	(31,839,000)	0	0
Amortization of loss	(38,942,000)	(28,995,000)	(20,599,000)
Amortization of prior service cost	(574,000)	(803,000)	(803,000)
Effect of settlement	48,729,000	0	0
Effect of curtailment	0	0	(1,083,000)
Total recognized in other comprehensive (income)/loss	(21,616,000)	226,109,000	100,394,000
Net periodic pension cost	87,228,000	45,008,000	37,843,000
Total recognized in net periodic benefit cost and other comprehensive loss	65,612,000	271,117,000	138,237,000
Estimated actuarial loss that will be amortized from accumulated other comprehensive loss into net periodic pension cost over the next fiscal year	40,000,000
Estimated prior service credit that will be amortized from accumulated other comprehensive loss into net periodic pension cost over the next fiscal year	$ 2,000,000