Deductible amount for casualty and catastrophic property programs.

No definition available.

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Namespace Prefix:	csx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Deductible amount for non-catastrophic property programs.

+ References

No definition available.

+ Details

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Namespace Prefix:	csx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Loss Contingency, Claims Filed, Number Of Entities

+ References

No definition available.

+ Details

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Namespace Prefix:	csx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of miles on the Passaic River tidal reach required to be studied as determined by the US Environmental Protection Agency.

+ References

No definition available.

+ Details

Name:	csx_NumberofmilespertainingtoPassaicRivertidalreachrequiredtobestudiedbyEPA
Namespace Prefix:	csx_
Data Type:	num:lengthItemType
Balance Type:	na
Period Type:	duration

- Definition

Site Contingency, Number of Miles Under Study

+ References

No definition available.

+ Details

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Namespace Prefix:	csx_
Data Type:	num:lengthItemType
Balance Type:	na
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

The estimated maximum amount of possible loss from the contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

+ Details

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

- Definition

The estimated minimum amount of possible loss from the contingency.

+ References

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
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Period Type:

- Details

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Period Type:

- Details

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Commitments and Contingencies (Details)	1 Months Ended		3 Months Ended
Commitments and Contingencies (Details)	Mar. 31, 2016 mi	May. 31, 2007 entity	Mar. 25, 2016 USD ($) mi
Loss Contingencies [Line Items]
Casualty and non catastrophic property deductible			$ 25,000,000
Casualty and catastrophic property deductible			$ 50,000,000
Environmental
Loss Contingencies [Line Items]
Number of miles pertaining to Passaic River tidal reach required to be studied by EPA \| mi			17
Number of miles subject to remediation \| mi	8
Pending Litigation
Loss Contingencies [Line Items]
Range of possible loss for certain legal proceedings, minimum			$ 2,000,000
Range of possible loss for certain legal proceedings, maximum			$ 86,000,000
Pending Litigation \| Fuel Surcharge Antitrust Litigation
Loss Contingencies [Line Items]
Class action lawsuits filed against U.S.-based Class I railroads, excluding CSXT (number of entities) \| entity		3