Percentage Of Grants With Performance Vesting Operating Ratio

No definition available.

Name:	csx_PercentageOfGrantsWithPerformanceVestingOperatingRatio
Namespace Prefix:	csx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Grants With Performance Vesting, Return On Assets

+ References

No definition available.

+ Details

Name:	csx_PercentageOfGrantsWithPerformanceVestingReturnOnAssets
Namespace Prefix:	csx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase (decrease) in payout percentage 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

No definition available.

+ Details

Name:	csx_ShareBasedCompensationArrangementbyShareBasedPaymentAwardEquityInstrumentsOtherthanOptionsPayoutPercentageIncreaseDecrease
Namespace Prefix:	csx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	csx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsPayoutPercentageofTarget
Namespace Prefix:	csx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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.

+ Details

Name:	csx_ShareBasedCompensationArrangementByShareBasePaymentAwardNumberOfEquivalentSharesOfCommonStockPerUnit
Namespace Prefix:	csx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.F)

-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ 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 (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_PlanNameAxis=csx_LongTermIncentivePlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Share-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		0 Months Ended
	Mar. 27, 2015	Mar. 28, 2014	Feb. 11, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	$ 8	$ 5
Income Tax Benefit	$ 3	$ 2
2017 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to downward adjustment (up to)	30.00%
2017 LTIP \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range for participants			0.00%
2017 LTIP \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range for participants			200.00%
2017 LTIP \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted			1,000,000
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			1,000,000
2017 LTIP \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted			312,000
Award vesting period			3 years