Debt and Credit Agreements (Details) (USD $)	9 Months Ended			1 Months Ended		1 Months Ended
	Sep. 30, 2011	Sep. 30, 2011 Current Liabilities	Sep. 30, 2011 Long Term Liabilities	May 31, 2011 Notes Payable 4.25% Note Due June 2021	May 20, 2011 Notes Payable 4.25% Note Due June 2021	May 31, 2011 Notes Payable 5.50% Note Due April 2041	May 20, 2011 Notes Payable 5.50% Note Due April 2041
Movement, Debt Instruments [Roll Forward]
Current Portion	$ 613,000,000	$ 613,000,000
Long-term Portion	8,051,000,000		8,051,000,000
Long-term Debt	8,664,000,000
Long-term debt issued	600,000,000	0	600,000,000
Long-term debt repaid	(595,000,000)	(595,000,000)	0
Reclassifications	0	481,000,000	(481,000,000)
Debt conversions to CSX stock	(5,000,000)	(5,000,000)	0
Discount and premium activity	(10,000,000)	0	(10,000,000)
Current Portion	494,000,000	494,000,000
Long-term Debt Portion	8,160,000,000		8,160,000,000
Long-term Debt	8,654,000,000
Notes issued, face amount					$ 350,000,000		$ 250,000,000
Notes issued, interest rate					4.25%		5.50%
Notes issued, maturity date				Jun. 01, 2021		Apr. 15, 2041