Asset Allocation for Company-Sponsored Pension Plans and Target Allocations by Asset Category (Detail)	12 Months Ended
	Dec. 30, 2012	Dec. 25, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total target allocation for 2012	100.00%
Equity securities	100.00%	100.00%
Equities Securities | Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Equity securities, target allocation for 2012	47.00%
Equity securities	51.00%	46.00%
Debt Securities | Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Equity securities, target allocation for 2012	35.00%
Equity securities	35.00%	39.00%
Other | Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Equity securities, target allocation for 2012	18.00%
Equity securities	14.00%	15.00%