Document And Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 30, 2016	Jan. 27, 2017	Jun. 24, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	CSX CORP
Entity Central Index Key	0000277948
Current Fiscal Year End Date	--12-30
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 24
Entity Common Stock, Shares Outstanding		926,446,993
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 30, 2016