Income Taxes (Income Tax Reconciliation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 30, 2011		Dec. 31, 2010		Dec. 25, 2009
Reconciliation between the statutory income tax rate and the effective income tax rate [Abstract]
Federal Income Taxes	$ 1,011		$ 891		$ 610
State Income Taxes	63		85		37
Corporate Reorganization	0		16		0
Other items	(8)		(9)	[1]	(29)	[1]
Income Tax Expense (Benefit)	1,066		983		618
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Federal Income Taxes (in hundreths)	35.00%		35.00%		35.00%
State Income Taxes (in hundreths)	2.20%		3.40%		2.10%
Corporate Reogranization (in hundreths)	0.00%		0.60%		0.00%
Other Items (in hundreths)	(0.30%)	[1]	(0.40%)	[1]	(1.60%)	[1]
Income Tax Expense/Rate (in hundreths)	36.90%		38.60%		35.50%
State and Local Jurisdiction [Member]
Reconciliation between the statutory income tax rate and the effective income tax rate [Abstract]
State Income Taxes	$ (14)

[1] Other items primarily include tax impacts from equity in Conrail and other partially owned subsidiaries’ earnings.