Casualty, Environmental and Other Reserves (Separation, Environmental and Other) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 30, 2011		Dec. 31, 2010		Dec. 25, 2009		Dec. 26, 2008
Contingencies [Line Items]
Other reserves	$ 641		$ 678		$ 737		$ 879
Separation Liabilities [Member]
Contingencies [Line Items]
Separation liabilities payment period range	5 to 10 years
Other reserves	48		60		73		87
Environmental Reserves [Member]
Contingencies [Line Items]
Environmental impaired site	246
Other reserves	83		107		97		100
Other Reserves [Member]
Contingencies [Line Items]
Other reserves	$ 138	[1]	$ 136	[1]	$ 108	[1]	$ 126	[1]

[1] Other reserve accruals were higher in 2010 due to an increase in freight rate reserves related to various rate disputes. These accruals were lower in 2009 primarily due to a reduction in freight loss and damage claims as a result of volume declines. These amounts are recorded as a reduction in revenue rather than expense because they represent liabilities for customer claims regarding the rates charged by the Company for its transportation services.