Summarized Consolidating Cash Flow (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 24, 2010
Operating Activities
Net Cash Provided by (Used in) Operating Activities	$ 2,585	$ 2,277
Investing Activities
Property Additions	(1,436)	(1,103)
Other Investing Activities	35	41
Net Cash Used in Investing Activities	(1,401)	(1,062)
Financing Activities
Long-term Debt Issued	600	0
Long-term Debt Repaid	(595)	(103)
Dividends Paid	(354)	(275)
Stock Options Exercised	27	21
Shares Repurchased	(1,564)	(1,123)
Other Financing Activities	(10)	(128)
Net Cash (Used in) Provided by Financing Activities	(1,896)	(1,608)
Net Decrease in Cash and Cash Equivalents	(712)	(393)
Cash and Cash Equivalents at Beginning of Period	1,292	1,029
Cash and Cash Equivalents at End of Period	580	636
CSX Corporation
Operating Activities
Net Cash Provided by (Used in) Operating Activities	1,062	242
Investing Activities
Property Additions	0	0
Other Investing Activities	(19)	(17)
Net Cash Used in Investing Activities	(19)	(17)
Financing Activities
Long-term Debt Issued	600
Long-term Debt Repaid	(507)	0
Dividends Paid	(362)	(281)
Stock Options Exercised	27	21
Shares Repurchased	(1,564)	(1,123)
Other Financing Activities	30	703
Net Cash (Used in) Provided by Financing Activities	(1,776)	(680)
Net Decrease in Cash and Cash Equivalents	(733)	(455)
Cash and Cash Equivalents at Beginning of Period	1,100	918
Cash and Cash Equivalents at End of Period	367	463
CSX Transportation
Operating Activities
Net Cash Provided by (Used in) Operating Activities	2,014	2,461
Investing Activities
Property Additions	(1,285)	(1,037)
Other Investing Activities	(90)	(86)
Net Cash Used in Investing Activities	(1,375)	(1,123)
Financing Activities
Long-term Debt Issued	0
Long-term Debt Repaid	(86)	(101)
Dividends Paid	(510)	(443)
Stock Options Exercised	0	0
Shares Repurchased	0	0
Other Financing Activities	(21)	(713)
Net Cash (Used in) Provided by Financing Activities	(617)	(1,257)
Net Decrease in Cash and Cash Equivalents	22	81
Cash and Cash Equivalents at Beginning of Period	118	30
Cash and Cash Equivalents at End of Period	140	111
Eliminations
Operating Activities
Net Cash Provided by (Used in) Operating Activities	(491)	(426)
Investing Activities
Property Additions	(151)	(66)
Other Investing Activities	144	144
Net Cash Used in Investing Activities	(7)	78
Financing Activities
Long-term Debt Issued	0
Long-term Debt Repaid	(2)	(2)
Dividends Paid	518	449
Stock Options Exercised	0	0
Shares Repurchased	0	0
Other Financing Activities	(19)	(118)
Net Cash (Used in) Provided by Financing Activities	497	329
Net Decrease in Cash and Cash Equivalents	(1)	(19)
Cash and Cash Equivalents at Beginning of Period	74	81
Cash and Cash Equivalents at End of Period	$ 73	$ 62