Summarized Consolidating Cash Flow Statements (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 27, 2013	Sep. 28, 2012
Operating Activities
Net Cash Provided by (Used in) Operating Activities	$ 2,499	$ 2,304
Investing Activities
Property Additions	(1,687)	(1,830)
Purchase of Short-term Investments	(809)	(78)
Proceeds from Sales of Short-term Investments	1,307	573
Other Investing Activities	(54)	10
Net Cash Provided by (Used in) Investing Activities	(1,243)	(1,325)
Financing Activities
Long-term Debt Issued	0	300
Long-term Debt Repaid	(779)	(481)
Dividends Paid	(448)	(415)
Stock Options Exercised	9	11
Share Repurchased	(224)	(500)
Other Financing Activities	(7)	16
Net Cash Used in Financing Activities	(1,449)	(1,069)
Net Decrease in Cash and Cash Equivalents	(193)	(90)
Cash and Cash Equivalents at Beginning of Period	784	783
Cash and Cash Equivalents at End of Period	591	693
CSX Corporation [Member]
Operating Activities
Net Cash Provided by (Used in) Operating Activities	871	429
Investing Activities
Property Additions	0	0
Purchase of Short-term Investments	(805)	(50)
Proceeds from Sales of Short-term Investments	1,240	525
Other Investing Activities	(4)	(6)
Net Cash Provided by (Used in) Investing Activities	431	469
Financing Activities
Long-term Debt Issued	0	300
Long-term Debt Repaid	(700)	(400)
Dividends Paid	(448)	(415)
Stock Options Exercised	9	11
Share Repurchased	(224)	(500)
Other Financing Activities	12	15
Net Cash Used in Financing Activities	(1,351)	(989)
Net Decrease in Cash and Cash Equivalents	(49)	(91)
Cash and Cash Equivalents at Beginning of Period	481	549
Cash and Cash Equivalents at End of Period	432	458
CSX Transportation [Member]
Operating Activities
Net Cash Provided by (Used in) Operating Activities	2,106	2,202
Investing Activities
Property Additions	(1,522)	(1,669)
Purchase of Short-term Investments	0	0
Proceeds from Sales of Short-term Investments	0	0
Other Investing Activities	(76)	78
Net Cash Provided by (Used in) Investing Activities	(1,598)	(1,591)
Financing Activities
Long-term Debt Issued	0	0
Long-term Debt Repaid	(79)	(79)
Dividends Paid	(548)	(536)
Stock Options Exercised	0	0
Share Repurchased	0	0
Other Financing Activities	(15)	3
Net Cash Used in Financing Activities	(642)	(612)
Net Decrease in Cash and Cash Equivalents	(134)	(1)
Cash and Cash Equivalents at Beginning of Period	235	154
Cash and Cash Equivalents at End of Period	101	153
Eliminations and Other [Member]
Operating Activities
Net Cash Provided by (Used in) Operating Activities	(478)	(327)
Investing Activities
Property Additions	(165)	(161)
Purchase of Short-term Investments	(4)	(28)
Proceeds from Sales of Short-term Investments	67	48
Other Investing Activities	26	(62)
Net Cash Provided by (Used in) Investing Activities	(76)	(203)
Financing Activities
Long-term Debt Issued	0	0
Long-term Debt Repaid	0	(2)
Dividends Paid	548	536
Stock Options Exercised	0	0
Share Repurchased	0	0
Other Financing Activities	(4)	(2)
Net Cash Used in Financing Activities	544	532
Net Decrease in Cash and Cash Equivalents	(10)	2
Cash and Cash Equivalents at Beginning of Period	68	80
Cash and Cash Equivalents at End of Period	$ 58	$ 82