Nature of Operations and Significant Accounting Policies (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 29, 2012 states mi	Jul. 01, 2011	Jun. 29, 2012 states mi	Jul. 01, 2011	Dec. 30, 2011
Background
Total number of rail route miles	21,000		21,000
Rail network states number	23		23
Fiscal Year
Number of weeks in fiscal year			P52W	P52W
Number of weeks in fiscal quarter	P13W	P13W	P26W	P26W
Comprehensive Earnings
Total comprehensive earnings, net of tax	$ 529,000,000	$ 519,000,000	$ 987,000,000	$ 925,000,000
Accumulated other comprehensive loss	(849,000,000)		(849,000,000)		(875,000,000)
Allowance for Doubtful Accounts
Current portion of allowance for doubtful accounts receivable	44,000,000		44,000,000		43,000,000
Other Items - Share Repurchases
Stock repurchases, share repurchase program			2,000,000,000
Stock repurchases, remaining authority			$ 434,000,000