XML 90 R72.htm IDEA: XBRL DOCUMENT v3.3.1.900
Pension, Retiree Medical and Savings Plans Retiree Medical Cost Trend Rates (Details)
12 Months Ended
Dec. 26, 2015
Dec. 27, 2014
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year [Abstract]    
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year 6.00% 6.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate 5.00% 5.00%