Casualty, Environmental and Other Reserves (Casualty) (Details) (Casualty [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 27, 2013 claims	Dec. 28, 2012	Dec. 30, 2011	Dec. 31, 2010
Casualty [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	$ 280	$ 325	$ 372	$ 375
Self-insured retention amount per injury	50
Individual claims expected to exceed self-insured retention amount	0
Change in estimate recorded to adjust reserves	$ 0	$ 0	$ 0