Description of the Plan (Details) - EBP 003 $ in Thousands	12 Months Ended
Dec. 31, 2025 USD ($) year
EBP, Description of Plan [Line Items]
ESOP, percent investment in company common stock	100.00%
Participant contribution, pretax, maximum annual compensation to total compensation, increment, percentage	1.00%
Participant compensation (in percentage)	3.50%
Additional contribution (in percentage)	3.00%
Disallowed reallocation period following transaction	30 days
Maximum borrowing, amount	$ 50
Note receivable from participant, period preceding loan	1 year
Account balance (in percentage)	50.00%
Primary residence, borrowing term	25 years
Basis spread on variable rate	1.00%
Payment of benefits, monthly installment period	240 months
Involuntary rollover limit	$ 7
Distribution request period	180 days
First 1% of Member's Eligible Contributions
EBP, Description of Plan [Line Items]
Matching contributions (in percentage)	100.00%
Participant compensation (in percentage)	1.00%
2% - 6% of Member's Eligible Contributions
EBP, Description of Plan [Line Items]
Matching contributions (in percentage)	50.00%
Employer Matching Contribution
EBP, Description of Plan [Line Items]
Vested (in percentage)	100.00%
Enhanced Contribution
EBP, Description of Plan [Line Items]
Vested (in percentage)	100.00%
Employer contribution vesting service period	3 years
Employer contribution maximum vesting age \| year	65
Minimum
EBP, Description of Plan [Line Items]
Participant contribution, maximum contribution to eligible compensation, percentage	1.00%
General loan, borrowing term	1 year
Minimum \| 2% - 6% of Member's Eligible Contributions
EBP, Description of Plan [Line Items]
Participant compensation (in percentage)	2.00%
Maximum
EBP, Description of Plan [Line Items]
Participant contribution, maximum contribution to eligible compensation, percentage	50.00%
General loan, borrowing term	5 years
Maximum \| 2% - 6% of Member's Eligible Contributions
EBP, Description of Plan [Line Items]
Participant compensation (in percentage)	6.00%

EBP, ESOP, Percent Investment In Company Common Stock

No definition available.

Name:	csx_EBPESOPPercentInvestmentInCompanyCommonStock
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum Vesting age of participant for company contribution and/ or investment earning in Company Matching Contributions, Fixed Rate Contributions, Discretionary Profit-Sharing Contributions, Qualified Non-Elective Contributions, and Disability Contributions.

+ References

No definition available.

+ Details

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

- Definition

EBP, Employer Contribution Vesting Percentage

+ References

No definition available.

+ Details

Name:	csx_EBPEmployerContributionVestingPercentage
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum Vesting service period for company contribution and/ or investment earning to the participant in Company Matching Contributions, Fixed Rate Contributions, Discretionary Profit-Sharing Contributions, Qualified Non-Elective Contributions, and Disability Contributions.

+ References

No definition available.

+ Details

Name:	csx_EBPEmployerContributionVestingServicePeriod
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Enhanced Contribution, Participant Compensation Matched, Percentage

+ References

No definition available.

+ Details

Name:	csx_EBPEnhancedContributionParticipantCompensationMatchedPercentage
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Involuntary Rollover, Distribution Request Period

+ References

No definition available.

+ Details

Name:	csx_EBPInvoluntaryRolloverDistributionRequestPeriod
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Involuntary Rollover Limit

+ References

No definition available.

+ Details

Name:	csx_EBPInvoluntaryRolloverLimit
Namespace Prefix:	csx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

EBP, Note Receivable From Participant, Account, Primary Residence, Maximum Borrowing Term

+ References

No definition available.

+ Details

Name:	csx_EBPNoteReceivableFromParticipantAccountPrimaryResidenceMaximumBorrowingTerm
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Note Receivable From Participant, General Loan, Borrowing Term

+ References

No definition available.

+ Details

Name:	csx_EBPNoteReceivableFromParticipantGeneralLoanBorrowingTerm
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Note Receivable From Participant, Period Preceding Loan

+ References

No definition available.

+ Details

Name:	csx_EBPNoteReceivableFromParticipantPeriodPrecedingLoan
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Participant Contribution, Maximum Annual Compensation to Total Compensation, Increment, Percentage

+ References

No definition available.

+ Details

Name:	csx_EBPParticipantContributionMaximumAnnualCompensationToTotalCompensationIncrementPercentage
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Participant Contribution, Maximum Contribution to Eligible Compensation, Percentage

+ References

No definition available.

+ Details

Name:	csx_EBPParticipantContributionMaximumContributionToEligibleCompensationPercentage
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Participant Loan, Basis Spread On Variable Rate

+ References

No definition available.

+ Details

Name:	csx_EBPParticipantLoanBasisSpreadOnVariableRate
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

EBP, Payment Of Benefits, Monthly Installment Period

+ References

No definition available.

+ Details

Name:	csx_EBPPaymentOfBenefitsMonthlyInstallmentPeriod
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Reallocations, Disallowed Reallocation Period Following Transaction

+ References

No definition available.

+ Details

Name:	csx_EBPReallocationsDisallowedReallocationPeriodFollowingTransaction
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionParticipantCompensationMatchedPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow to total participant account balance.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingToTotalAccountPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=csx_EBP003Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	csx_EBPEmployerContributionTypeAxis=csx_EBPFirst1OfMembersEligibleContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	csx_EBPEmployerContributionTypeAxis=csx_EBP26OfMembersEligibleContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	csx_EBPEmployerContributionTypeAxis=csx_EBPEmployerMatchingContributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	csx_EBPEmployerContributionTypeAxis=csx_EBPEnhancedContributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Balance Type:
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