Derivative, Number Of Fair Value Hedges

No definition available.

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

- Definition

Fair value of all asset derivatives designated as cash flow hedging instruments.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

Fair value as of the balance sheet date of all derivative liabilities designated as interest rate fair value hedging instruments.

+ References

+ Details

Name:	us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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+ Details

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

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after tax and before reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=csx_A325NotesDue2027Member
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=csx_UnsecuredRevolvingCreditFacilityDue2024Member
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Data Type:	na
Balance Type:
Period Type:

- Details

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Period Type:

- Details

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- Details

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- Details

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Period Type:

- Details

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Debt and Credit Agreements - Narrative (Details)	3 Months Ended
Debt and Credit Agreements - Narrative (Details)	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($) swap	Feb. 28, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)
Commercial Paper
Line of Credit Facility
Maximum borrowing capacity of credit facility	$ 1,000,000,000
Borrowings outstanding	0
Fixed Rate Notes Due Between 2036 and 2040
Line of Credit Facility
Debt issued	800,000,000	$ 800,000,000		$ 800,000,000
3.25% Notes Due 2027
Line of Credit Facility
Debt issued					$ 850,000,000
Debt interest rate					3.25%
Unsecured Revolving Credit Facility Expiring March 2024 \| Credit Facility
Line of Credit Facility
Maximum borrowing capacity of credit facility			$ 1,200,000,000	1,200,000,000
Borrowings outstanding	0
Fixed-to-Floating Interest Rate Swap \| Fair Value Hedging
Line of Credit Facility
Derivative, number of fair value hedges \| swap		5
Derivative, term of contract (in years)		10 years
Designated as Hedging Instrument \| Fixed-to-Floating Interest Rate Swap \| Fair Value Hedging
Line of Credit Facility
Fair value hedge derivative instrument liabilities at fair value	103,000,000			118,000,000
Designated as Hedging Instrument \| Forward Starting Interest Rate Swap \| Cash Flow Hedge
Line of Credit Facility
Cash flow hedge derivative instrument assets at fair value	124,000,000			$ 127,000,000
Unrealized gains (losses) recorded net of tax in other comprehensive income related to hedge	$ (3,000,000)	$ 21,000,000
Designated as Hedging Instrument \| Interest Rate Swap \| Cash Flow Hedge
Line of Credit Facility
Aggregate notional value of interest forward interest rate swap					$ 340,000,000