Share-Based Compensation - Narrative (Details)	9 Months Ended
Sep. 23, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	2,400,000
Fair value of stock options (in dollars per share) \| $ / shares	$ 4.68
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Term of stock options (in years)	10 years
2016 - 2018 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to downward adjustment (up to)	30.00%
2016 - 2018 LTIP \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range for participants (as a percent)	0.00%
2016 - 2018 LTIP \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range for participants (as a percent)	200.00%
2016 - 2018 LTIP \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	839,000
Percentage of grants with performance vesting, operating ratio	50.00%
Percentage of grants with performance vesting, return on assets	50.00%
Performance unit equivalent of CSX common stock (in shares)	1
2016 - 2018 LTIP \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	419,000

Percentage Of Grants With Performance Vesting Operating Ratio

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Percentage Of Grants With Performance Vesting, Return On Assets

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- Definition

Share Based Compensation Arrangement by Share Base Payment Award Number of Equivalent Shares of Common Stock Per Unit (e.g. performance units, restricted stock units, etc.).

+ References

No definition available.

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- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Payout Percentage Downward Adjustment

+ References

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Payout Percentage of Target

+ References

No definition available.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- 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.

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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