Nature of Operations and Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 30, 2012 mi states	Apr. 01, 2011	Dec. 30, 2011
Background
Total number of rail route miles	21,000
Rail network states number	23
Fiscal Year
Number of weeks in fiscal year	P52W		P52W
Number of weeks in fiscal quarter	P13W	P13W
Comprehensive Earnings
Total comprehensive earnings, net of tax	$ 458	$ 406
Accumulated other comprehensive loss	(866)		(875)
Other Items - Share Repurchases
Share repurchases	300
Allowance for Doubtful Accounts
Current portion of allowance for doubtful accounts receivable	$ 42		$ 43