Properties (Significant Property Disposition) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended					0 Months Ended	1 Months Ended	0 Months Ended
	Dec. 30, 2011 mi	Dec. 31, 2010	Dec. 25, 2009	Dec. 30, 2011 Other Current Liabilities [Member]	Dec. 30, 2011 Other Long-term Liabilities [Member]	Nov. 30, 2011 SunRail Transaction - Sale of Corridor [Member] mi	Dec. 30, 2011 SunRail Transaction - Sale of Corridor [Member]	Nov. 30, 2011 SunRail Transaction - Sale of Corridor [Member] Maximum [Member]	Nov. 30, 2011 SunRail Transaction - Sale of Corridor [Member] Cash [Member]	Nov. 30, 2011 SunRail Transaction - Sale of Corridor [Member] Accounts Receivable [Member]
Significant Acquisitions and Disposals [Line Items]
Rail Route Network, Distance	21,000					61
Property, Plant and Equipment, Disposals						$ 173
Proceeds from Sale of Property, Plant, and Equipment	240	108	45						148
Noncash or Part Noncash Divestiture, Amount of Consideration Received										25
Government Grants Received for Property Additions								259
Capital Expenditure Incurred to Date, Percentage of Total Investment Obligation							9.00%
Gain (Loss) on Disposition of Property		(30)	0				14
Deferred Gain on Sale of Real Estate [Abstract]
Deferred Gain on sale of real estate				$ 95	$ 37	$ 146	$ 132