XML 106 R88.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Fair Value Measurements (Pension Plan Assets) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Dec. 26, 2014 | Dec. 27, 2013
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | $ 2,504 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets | $ 2,500 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Equity [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Investment Committee equity target allocation percentage of pension assets | 70.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_EquityMember |
Pension plan assets at fair value | 1,715 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_EquityMember | 1,619 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_EquityMember
Information technology [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 177 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockInformationTechnologyMember | 173 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockInformationTechnologyMember
Health care [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 133 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockHealthCareMember | 126 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockHealthCareMember
Consumer discretionary [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 125 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerDiscretionaryMember | 152 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerDiscretionaryMember
Financials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 116 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockFinancialsMember | 116 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockFinancialsMember
Industrials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 90 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockIndustrialsMember | 108 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockIndustrialsMember
Energy [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 51 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockEnergyMember | 59 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockEnergyMember
Consumer staples [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 42 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerStaplesMember | 43 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerStaplesMember
Materials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 20 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockMaterialsMember | 29 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockMaterialsMember
Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 33 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_EquitySecurityOtherMember | 31 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_EquitySecurityOtherMember
Fixed Income Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Investment Committee equity target allocation percentage of pension assets | 30.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember |
Pension plan assets at fair value | 740 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember | 795 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember
Mutual funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 20 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_MutualFundsMember | 17 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_MutualFundsMember
Cash equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 1 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashEquivalentsMember | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashEquivalentsMember
Common trust funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 611 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonTrustFundsMember | 553 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonTrustFundsMember
Corporate bonds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 539 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember | 568 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember
Partnerships [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 365 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_PartnershipsMember | 314 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_PartnershipsMember
Government securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 164 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USTreasuryAndGovernmentMember | 186 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USTreasuryAndGovernmentMember
Asset-backed securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 15 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_AssetBackedSecuritiesMember | 24 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_AssetBackedSecuritiesMember
Derivatives and other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 2 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_DerivativesAndOtherMember | 1 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_DerivativesAndOtherMember
Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 808 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 854 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Information technology [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 177 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockInformationTechnologyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 173 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockInformationTechnologyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Health care [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 133 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockHealthCareMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 126 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockHealthCareMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Consumer discretionary [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 125 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerDiscretionaryMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 152 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerDiscretionaryMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Financials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 116 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockFinancialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 116 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockFinancialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Industrials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 90 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockIndustrialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 108 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockIndustrialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Energy [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 51 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockEnergyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 59 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockEnergyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Consumer staples [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 42 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerStaplesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 43 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerStaplesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Materials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 20 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockMaterialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 29 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockMaterialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 33 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_EquitySecurityOtherMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 31 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_EquitySecurityOtherMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Mutual funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 20 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_MutualFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 17 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_MutualFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Cash equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 1 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashEquivalentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashEquivalentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Common trust funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonTrustFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonTrustFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Corporate bonds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Partnerships [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_PartnershipsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_PartnershipsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Government securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USTreasuryAndGovernmentMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USTreasuryAndGovernmentMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Asset-backed securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_AssetBackedSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_AssetBackedSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 1 [Member] | Derivatives and other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_DerivativesAndOtherMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_DerivativesAndOtherMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 1,696 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 1,646 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Information technology [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockInformationTechnologyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockInformationTechnologyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Health care [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockHealthCareMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockHealthCareMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Consumer discretionary [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerDiscretionaryMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerDiscretionaryMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Financials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockFinancialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockFinancialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Industrials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockIndustrialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockIndustrialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Energy [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockEnergyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockEnergyMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Consumer staples [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerStaplesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockConsumerStaplesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Materials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockMaterialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonStockMaterialsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_EquitySecurityOtherMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_EquitySecurityOtherMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Mutual funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_MutualFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_MutualFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Cash equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashEquivalentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 0 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashEquivalentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Common trust funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 611 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonTrustFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 553 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = csx_CommonTrustFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Corporate bonds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension plan assets at fair value | 539 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 568 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Level 2 [Member] | Partnerships [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 2 [Member] | Government securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 2 [Member] | Asset-backed securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 2 [Member] | Derivatives and other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Information technology [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Health care [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Consumer discretionary [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Financials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Industrials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Energy [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Consumer staples [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Materials [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Mutual funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Cash equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Common trust funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Corporate bonds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Partnerships [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Government securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Asset-backed securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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Level 3 [Member] | Derivatives and other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
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- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930 + Details
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