Summarized Consolidating Cash Flow Statements (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 27, 2014	Jun. 28, 2013
Operating Activities
Net Cash Provided by (Used in) Operating Activities	$ 1,445	$ 1,579
Investing Activities
Property Additions	(956)	(1,085)
Purchase of Short-term Investments	(360)	(690)
Proceeds from Sales of Short-term Investments	646	904
Other Investing Activities	20	(50)
Net Cash Provided by (Used in) Investing Activities	(650)	(921)
Financing Activities
Long-term debt repaid	(244)	(455)
Dividends Paid	(311)	(296)
Stock Options Exercised	0	9
Shares Repurchased	(257)	(95)
Other Financing Activities	(2)	9
Net Cash Used in Financing Activities	(814)	(828)
Net Decrease in Cash and Cash Equivalents	(19)	(170)
Cash and Cash Equivalents at Beginning of Period	592	784
Cash and Cash Equivalents at End of Period	573	614
CSX Corporation
Operating Activities
Net Cash Provided by (Used in) Operating Activities	453	582
Investing Activities
Property Additions	0	0
Purchase of Short-term Investments	(360)	(685)
Proceeds from Sales of Short-term Investments	637	840
Other Investing Activities	0	(2)
Net Cash Provided by (Used in) Investing Activities	277	153
Financing Activities
Long-term debt repaid	(200)	(400)
Dividends Paid	(311)	(296)
Stock Options Exercised		9
Shares Repurchased	(257)	(95)
Other Financing Activities	6	7
Net Cash Used in Financing Activities	(762)	(775)
Net Decrease in Cash and Cash Equivalents	(32)	(40)
Cash and Cash Equivalents at Beginning of Period	439	481
Cash and Cash Equivalents at End of Period	407	441
CSX Transportation
Operating Activities
Net Cash Provided by (Used in) Operating Activities	1,276	1,319
Investing Activities
Property Additions	(867)	(988)
Purchase of Short-term Investments	0	0
Proceeds from Sales of Short-term Investments	0	0
Other Investing Activities	(58)	(35)
Net Cash Provided by (Used in) Investing Activities	(925)	(1,023)
Financing Activities
Long-term debt repaid	(44)	(55)
Dividends Paid	(285)	(365)
Stock Options Exercised		0
Shares Repurchased	0	0
Other Financing Activities	(10)	4
Net Cash Used in Financing Activities	(339)	(416)
Net Decrease in Cash and Cash Equivalents	12	(120)
Cash and Cash Equivalents at Beginning of Period	91	235
Cash and Cash Equivalents at End of Period	103	115
Eliminations and Other
Operating Activities
Net Cash Provided by (Used in) Operating Activities	(284)	(322)
Investing Activities
Property Additions	(89)	(97)
Purchase of Short-term Investments	0	(5)
Proceeds from Sales of Short-term Investments	9	64
Other Investing Activities	78	(13)
Net Cash Provided by (Used in) Investing Activities	(2)	(51)
Financing Activities
Long-term debt repaid	0	0
Dividends Paid	285	365
Stock Options Exercised		0
Shares Repurchased	0	0
Other Financing Activities	2	(2)
Net Cash Used in Financing Activities	287	363
Net Decrease in Cash and Cash Equivalents	1	(10)
Cash and Cash Equivalents at Beginning of Period	62	68
Cash and Cash Equivalents at End of Period	$ 63	$ 58