Plan’s Percentage of Investment in the Master Trust’s Net Assets EBP, Interest in Master Trust Investment Gain, Percentage EBP, Interest in Master Trust Investment Gain, Percentage Entity tax identification number Entity Tax Identification Number Investments, at fair value: EBP, Investment, Fair Value General loan, borrowing term EBP, Note Receivable From Participant, General Loan, Borrowing Term EBP, Note Receivable From Participant, General Loan, Borrowing Term Maximum Maximum [Member] Legal Entity [Axis] Legal Entity [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] EBP, Description of Plan [Table] EBP, Description of Plan [Table] Mutual Funds Mutual Fund [Member] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Accounting Standard Update and Change in Accounting Principle [Table] EBP, Accounting Standard Update and Change in Accounting Principle [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] Total Deductions EBP, Change in Net Asset Available for Benefit, Decrease Maximum borrowing, amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Fair Value Measurements EBP, Investment, Fair Value and NAV [Text Block] Accrued expenses EBP, Accrued Expense EBP, Fully Benefit-Responsive Investment Contract [Abstract] EBP, Nonconsolidated, Plan Interest in Master Trust EBP, Nonconsolidated, Plan Interest in Master Trust [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Fully Benefit-Responsive Investment Contracts EBP, Fully Benefit-Responsive Investment Contract [Text Block] EBP, Investment, Fair Value and NAV [Abstract] Involuntary rollover limit EBP, Involuntary Rollover Limit EBP, Involuntary Rollover Limit Total Assets EBP, Asset ASSETS EBP, Asset [Abstract] Statistical Measurement [Axis] Statistical Measurement [Axis] Additions EBP, Change in Net Asset Available for Benefit, Increase [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Master Trust [Line Items] EBP, Master Trust [Line Items] Total Liabilities EBP, Liability ESOP, percent investment in company common stock EBP, ESOP, Percent Investment In Company Common Stock EBP, ESOP, Percent Investment In Company Common Stock Amendment Flag Amendment Flag Basis of Presentation EBP, Basis of Accounting [Policy Text Block] Due from brokers for securities sold EBP, Investment Sale, Receivable EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] Investment in Master Trust (Note 3) EBP, Investment, Plan Interest in Master Trust, Fair and Contract Value EBP, Description of Plan and Accounting Change [Abstract] Receivables EBP, Receivable [Abstract] Schedule of Fair Value Hierarchy of Master Trust EBP, Investment, Fair Value and NAV [Table Text Block] Common stock Common Stock [Member] Investments [Domain] Investments [Domain] Other Common Stock EBP, Nonemployer, Common Stock [Member] EBP, Master Trust [Abstract] Use of Estimates EBP, Use of Estimate [Policy Text Block] EBP, Schedule of Asset Held for Investment EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Risks and Uncertainties EBP, Risk and Uncertainty [Text Block] Accrued income EBP, Investment Income, Receivable Minimum Minimum [Member] Investment Type [Axis] Investment Type [Axis] Disallowed reallocation period following transaction EBP, Reallocations, Disallowed Reallocation Period Following Transaction EBP, Reallocations, Disallowed Reallocation Period Following Transaction Employer contribution, noncash EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Noncash Interest on notes receivable from members EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Basis spread on variable rate EBP, Participant Loan, Basis Spread On Variable Rate EBP, Participant Loan, Basis Spread On Variable Rate Member contributions EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Net increase in the fair value of investments: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Interest, dividend, and other income EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] Description of the Plan EBP, Description of Plan [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] Primary residence, borrowing term EBP, Note Receivable From Participant, Account, Primary Residence, Maximum Borrowing Term EBP, Note Receivable From Participant, Account, Primary Residence, Maximum Borrowing Term Interest income on investment EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Investment EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] CSX Common Stock EBP, Employer, Common Stock [Member] EBP, Schedule of Asset Held for Investment [Abstract] Total Additions EBP, Change in Net Asset Available for Benefit, Increase Fees and expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Stable Value Fund, at contract value: EBP, Investment, Contract Value Payment of benefits, monthly installment period EBP, Payment Of Benefits, Monthly Installment Period EBP, Payment Of Benefits, Monthly Installment Period Document Information [Line Items] Document Information [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Table] EBP, Risk and Uncertainty [Table] Investment in Master Trust EBP, Master Trust [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] EBP, Fully Benefit-Responsive Investment Contract [Line Items] EBP, Fully Benefit-Responsive Investment Contract [Line Items] Employer contributions EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash EBP, Tax Status [Table] EBP, Tax Status [Table] Net Increase EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Related Party and Party-In Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Text Block] EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Employer contributions EBP, Employer Contribution, Receivable Investments EBP, Investment, Fair Value [Abstract] Dividend income on investment EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment Distributions to members EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Total assets at fair value EBP, Investment, Plan Interest in Master Trust, Fair Value Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Note receivable from participant, period preceding loan EBP, Note Receivable From Participant, Period Preceding Loan EBP, Note Receivable From Participant, Period Preceding Loan EBP 004 EBP 004 [Member] EBP 004 EBP, Statement of Net Asset Available for Benefit [Abstract] Due to brokers for securities purchased EBP, Liability for Investment Purchase EBP, Tax Status [Abstract] Current value EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution EBP, Master Trust [Table] EBP, Master Trust [Table] Total Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] EBP, Accounting Standard Update and Change in Accounting Principle [Line Items] EBP, Accounting Standard Update and Change in Accounting Principle [Line Items] Document Type Document Type Entity Central Index Key Entity Central Index Key Distribution request period EBP, Involuntary Rollover, Distribution Request Period EBP, Involuntary Rollover, Distribution Request Period Interest rate EBP, Asset Held for Investment, Participant Loan, Interest Rate Common Collective Trusts Common Collective Trust [Member] EBP, Risk and Uncertainty [Abstract] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] Deductions EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] Notes receivable from members EBP, Note Receivable from Participant EBP, Nonconsolidated, Master Trust EBP, Nonconsolidated, Master Trust [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Summary of Significant Accounting Policies EBP, Summary of Accounting Policy [Text Block] Entity Registrant Name Entity Registrant Name Participant contribution, maximum annual compensation to total compensation, percentage EBP, Participant Contribution, Maximum Contribution to Eligible Compensation, Percentage EBP, Participant Contribution, Maximum Contribution to Eligible Compensation, Percentage Schedule of Financial Information of Master Trust EBP, Master Trust [Table Text Block] LIABILITIES EBP, Liability [Abstract] Vested (in percentage) EBP, Employer Contribution Vesting Percentage EBP, Employer Contribution Vesting Percentage Income Tax Status EBP, Tax Status [Text Block] Account balance (in percentage) EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Document Information [Table] Document Information [Table] Notes Receivable from Members EBP, Note Receivable from Participant [Policy Text Block] Net gain from investment in Master Trust (Note 3) Total investment gain for the Master Trust EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment Transfers to Plan EBP, Change in Net Asset Available for Benefit, Transfer to Plan EBP, Change in Net Asset Available for Benefit, Transfer to Plan EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Net Assets Available for Benefits at End of Year Net Assets Available for Benefits at Beginning of Year Net Assets Available for Benefits at End of Year EBP, Net Asset Available for Benefit Entity [Domain] Entity [Domain] Minimum crediting rate EBP, Fully Benefit-Responsive Investment Contract, Minimum Crediting Rate EBP, Fully Benefit-Responsive Investment Contract, Minimum Crediting Rate Participant contribution, pretax, maximum annual compensation to total compensation, increment, percentage EBP, Participant Contribution, Maximum Annual Compensation to Total Compensation, Increment, Percentage EBP, Participant Contribution, Maximum Annual Compensation to Total Compensation, Increment, Percentage NAV Fair Value Measured at Net Asset Value Per Share [Member] EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] Plan’s Percentage of Investment in the Master Trust’s Net Assets EBP, Interest in Master Trust, Percentage EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items] Transfers from the Plan EBP, Change in Net Asset Available for Benefit, Transfer From Plan EBP, Change in Net Asset Available for Benefit, Transfer From Plan