Other Postretirement Benefits - Schedule of Assumptions Used (Details) (Other Postretirement Benefit Plans, Defined Benefit [Member])	12 Months Ended
	Dec. 25, 2011	Dec. 26, 2010	Dec. 27, 2009
Other Postretirement Benefit Plans, Defined Benefit [Member]
Other Postretirement Benefits
Discount rate used to calculate net periodic benefit cost	5.14%	5.92%	6.67%
Discount rate used to calculate benefit obligation	4.64%	5.35%
Estimated increase in compensation level used to calculate benefit obligation	3.50%	3.50%
Estimated increase in compensation level use to calculate net periodic benefit cost	3.50%	3.50%	3.50%