Related Party Transactions Related Party Transactions, Narrative (Details)	Dec. 30, 2011
Related Party Transaction [Line Items]
Percentage Economic Interest In Related Party	42.00%
Percentage Voting Interest In Related Party	50.00%

The percentage of economic interest in related party owned by company.

No definition available.

Name:	csx_PercentageEconomicInterestInRelatedParty
Namespace Prefix:	csx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant