Total number of claims expected to exceed self-insured retention amount, as of the balance sheet date.

No definition available.

Name:	csx_LossContingencyNumberOfClaimsExpectedToExceedSelfInsuredRetentionAmount
Namespace Prefix:	csx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of environmentally impaired sites at which the Company has been identified as a potentially responsible party.

+ References

No definition available.

+ Details

Name:	csx_NumberOfImpairedSites
Namespace Prefix:	csx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Self insured retention amount for casualty and catastrophic property programs.

+ References

No definition available.

+ Details

Name:	csx_SelfInsuredRetention
Namespace Prefix:	csx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=csx_TotalCasualtyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_EnvironmentalIssueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=csx_OtherReservesMember
Namespace Prefix:
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Period Type:

Casualty, Environmental and Other Reserves - Narrative (Details)	Jun. 01, 2018 USD ($)	May 31, 2018 USD ($)	Mar. 31, 2019 USD ($) claim site	Dec. 31, 2018 USD ($)
All Contingencies Reserves [Line Items]
Total reserves			$ 319,000,000	$ 324,000,000
Casualty
All Contingencies Reserves [Line Items]
Total reserves			$ 195,000,000	199,000,000
Self-insured retention amount, per occurrence	$ 75,000,000	$ 50,000,000
Number of individual claims expected to exceed self insured retention amount \| claim			0
Environmental
All Contingencies Reserves [Line Items]
Total reserves			$ 80,000,000	80,000,000
Environmental impaired sites \| site			226
Other
All Contingencies Reserves [Line Items]
Total reserves			$ 44,000,000	$ 45,000,000