Employee Benefit Plans (Details 2)
 12 Months Ended
Dec. 25, 2011
Dec. 26, 2010
Defined benefit plan [Member]
    
Rate Assumptions    
Weighted-average discount rate used in determining net periodic cost 6.10% 6.40%
Weighted-average expected long-term rate of return on plan assets in determination of net periodic costs 7.50% 7.50%
Weighted-average rate of compensation increase(1) 0.00% 0.00%
Weighted-average discount rate used in determination of projected benefit obligation 5.30% 6.10%
Other Postretirement Benefit Plans, Defined Benefit [Member]
    
Rate Assumptions    
Weighted-average discount rate used in determining net periodic cost 6.10% 6.40%
Weighted-average expected long-term rate of return on plan assets in determination of net periodic costs 0.00% 0.00%
Weighted-average rate of compensation increase(1) 0.00% 0.00%
Weighted-average discount rate used in determination of projected benefit obligation 5.30% 6.10%
Assumed health care cost trend:    
Initial trend 9.00% 9.00%
Ultimate trend rate 5.00% 5.00%