Compensation and Retirement Disclosure [Abstract] Employment Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Subsequent Event [Table] Subsequent Event [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] SEC Debt Shelf Registration SEC Debt Shelf Registration [Member] SEC Debt Shelf Registration [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Financing [Axis] Financing [Axis] Financing [Domain] Financing [Domain] Authorization of Debt Authorization of Debt [Member] Authorization of Debt [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Additional debt securities authorized for issuance by the Board of Managers Additional Debt Securities Authorized For Issuance By The Board of Managers Additional Debt Securities Authorized For Issuance By The Board of Managers Remaining amount of debt securities that may be issued Debt Instrument, Unused Borrowing Capacity, Amount Receivables [Abstract] Accounts Receivable, Net Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Allowance for bill adjustments and uncollectible accounts Allowance for Bill Adjustments and Doubtful Accounts Receivable, Current A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that have bill adjustments or are expected to be uncollectible. Accounts receivable greater than 90 days old Accounts Receivable, Current, Greater than 90 Days Past Due Accounts Receivable, Current, Greater than 90 Days Past Due Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Statement of Cash Flows [Abstract] Statement [Table] Statement [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Successor Successor [Member] Predecessor Predecessor [Member] Statement [Line Items] Statement [Line Items] OPERATING ACTIVITIES Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss) Attributable to Parent Adjustments to reconcile net income to net cash provided by operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Deferred income taxes Deferred Income Tax Expense (Benefit) Long-term casualty and environmental liabilities, net Long term casualty and environmental liabilities, net The net change during the reporting period in the amount of noncurrent costs accrued for casualty, environmental and other loss contingencies. Contribution to defined benefit pension plan Pension Contributions Other, net Other Operating Activities, Cash Flow Statement Changes in current assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable, net Increase (Decrease) in Accounts Receivable Materials and supplies Increase (Decrease) in Materials and Supplies Other current assets Increase (Decrease) in Other Current Assets Accounts payable and other current liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities INVESTING ACTIVITIES Net Cash Provided by (Used in) Investing Activities [Abstract] Capital expenditures excluding equipment Capital Expenditures Excluding Equipment The cash outflow associated with the acquisition of long-lived, physical assets, excluding equipment, that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Acquisition of equipment Acquisition of equipment The cash outflow associated with the acquisition of equipment which includes locomotive, freight cars and other equipment, some or all of which may be sold and leased back by the Company through either an operating or capital lease. Other, net Payments for (Proceeds from) Other Investing Activities Net cash used for investing activities Net Cash Provided by (Used in) Investing Activities FINANCING ACTIVITIES Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from issuance of long-term debt Proceeds from Issuance of Long-term Debt Payments on long-term debt Repayments of Long-term Debt Cash distributions Cash Distributions/ Dividends Paid The cash outflow from the distribution of an entity's earnings in the form of dividends to common shareholders or distributions to the parent company. Other, net Proceeds from (Payments for) Other Financing Activities Net cash used for financing activities Net Cash Provided by (Used in) Financing Activities Decrease in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents: Cash and Cash Equivalents, at Carrying Value [Abstract] Beginning of period Cash and Cash Equivalents, at Carrying Value End of period SUPPLEMENTAL CASH FLOW INFORMATION Supplemental Cash Flow Information [Abstract] Interest paid, net of amounts capitalized Interest Paid, Net Capital investments accrued but not yet paid Capital Expenditures Incurred but Not yet Paid Income taxes paid, net of refunds Income Taxes Paid, Net Non-cash asset financing Capital Lease Obligations Incurred Consolidated Statements of Comprehensive Income [Abstract] Consolidated Statements of Comprehensive Income [Abstract] Net income Other comprehensive income: Other Comprehensive Income (Loss), Net of Tax [Abstract] Change in amortization of accumulated actuarial losses, net of tax expense of $0 million, $0 million, $2 million and $0 million, respectively Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax Change in fuel hedge mark-to-market, net of tax benefit of $2 million, $26 million, $7 million and $1 million, respectively Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Change in other comprehensive income of equity method investees Change in Other Comprehensive Income of Equity Method Investees Change in Other Comprehensive Income of Equity Method Investees Other comprehensive loss, net of tax Other Comprehensive Income (Loss), Net of Tax Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Derivative Instruments and Hedging Activities Disclosure [Abstract] Fuel Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Income Statement [Abstract] Revenues Revenue, Net Operating expenses: Operating Expenses [Abstract] Compensation and benefits Labor and Related Expense Fuel Fuel Costs Purchased services Purchased services The amount of expense for contract services provided to the Company. Equipment rents Equipment rents Rent paid for freight cars owned by other railroads or private companies, net of rents received, including lease expenses primarily for locomotives, railcars, containers and trailers. Materials and other Materials and other Materials and other operating expenses not separately disclosed. This element is used when other, more specific, elements are not appropriate. Total operating expenses Operating Expenses Operating income Operating Income (Loss) Interest expense Interest and Debt Expense Other expense, net Other Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Guarantee Entity Name [Axis] Guarantee Entity Name [Axis] Guarantee Entity Name [Axis] Guarantee Entity Name [Domain] Guarantee Entity Name [Domain] Guarantee Entity Name [Domain] Kinder Morgan Energy Partners, L.P. Kinder Morgan Energy Partners, L.P. [Member] Kinder Morgan Energy Partners, L.P. [Member] Chevron Phillips Chemical Company, LP Chevron Phillips Chemical Company, LP [Member] Chevron Phillips Chemical Company, LP [Member] All Other Guarantee Entities All Other Guarantee Entities [Member] All Other Guarantee Entities [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Payment Guarantee Payment Guarantee [Member] Indemnification Agreement Indemnification Agreement [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] BNSF Ownership Percentage Noncontrolling Interest, Ownership Percentage by Parent Principal Amount Guaranteed Principal Amount Guaranteed Principal Amount Guaranteed Maximum Future Payments Guarantor Obligations, Maximum Exposure, Undiscounted Maximum Recourse Amount Maximum Recourse Amount Maximum Recourse Amount Remaining Term (in years) Remaining Term Remaining Term Capitalized Obligations Guarantor Obligations, Current Carrying Value Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Accounts receivable, net Accounts Receivable, Net, Current Materials and supplies Materials, Supplies, and Other Current portion of deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Current Other current assets Other Assets, Current Total current assets Assets, Current Property and equipment, net of accumulated depreciation of $1,279 and $1,056, respectively Property, Plant and Equipment, Net Goodwill Goodwill Intangible assets, net Finite-Lived Intangible Assets, Net Other assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable and other current liabilities Accounts Payable and Accrued Liabilities, Current Long-term debt due within one year Long-term Debt and Capital Lease Obligations, Current Total current liabilities Liabilities, Current Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Long-term debt Long-term Debt and Capital Lease Obligations Intangible liabilities, net Intangible liabilities, net The aggregate sum of gross carrying value of a major finite-lived intangible liability class, less accumulated amortization and any impairment charges. Casualty and environmental liabilities Casualty and environmental liabilities Noncurrent portion of costs accrued as of the balance sheet date for casualty, environmental and other loss contingencies. Pension and retiree health and welfare liability Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent Other liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies (see Notes 2, 6 and 7) Commitments and Contingencies Equity: Stockholders' Equity Attributable to Parent [Abstract] Member's Equity Members' Equity Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total equity Stockholders' Equity Attributable to Parent Total liabilities and equity Liabilities and Equity Entities [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Public Float Entity Public Float Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Environmental Issue Environmental Issue [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of alleged environmental contamination sites (in sites) Administrative Judicial and Other Mandatory Cleanup Efforts Total Sites Administrative, Judicial and Other Mandatory Cleanup Efforts, Total Sites Number of environmental superfund sites (in sites) Administrative Judicial and Other Mandatory Cleanup Efforts Superfund Sites Administrative, Judicial and Other Mandatory Cleanup Efforts, Superfund Sites Liability for third-party tort claims Recorded Liability For Third Party Environmental Tort Claims Recorded Liability For Third Party Environmental Tort Claims Accrued obligations for environmental matters, current liabilities Accrued Environmental Loss Contingencies, Current Reduction In expense due to settlements of environmental liabilities Reduction In Expense Due to Settlements of Environmental Liabilities Reduction In Expense Due to Settlements of Environmental Liabilities Estimated time frame for accrued cost distributions Site Contingency, Estimated Time Frame for Accrued Cost Distributions Site Contingency, Estimated Time Frame for Accrued Cost Distributions Future costs for environmental liabilities, minimum Loss Contingency, Range of Possible Loss, Minimum Future costs for environmental liabilities, maximum Loss Contingency, Range of Possible Loss, Maximum Accrual for Environmental Loss Contingencies [Roll Forward] Accrual for Environmental Loss Contingencies [Roll Forward] Beginning balance Accrual for Environmental Loss Contingencies Accruals Accrual For Environmental Loss Contingencies Provision Accrual For Environmental Loss Contingencies Provision Payments Accrual for Environmental Loss Contingencies, Payments Ending balance Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] Schedule of Finite-Lived Intangible Assets and Liabilities Schedule of Finite-Lived Intangible Assets and Liabilities [Table Text Block] Schedule of Finite-Lived Intangible Assets and Liabilities [Table Text Block] Schedule of Finite-Lived Intangible Assets and Liabilities Amortization Expense Schedule of Finite-Lived Intangible Assets and Liabilities Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets and Liabilities Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets and Liabilities, Future Amortization Expense Schedule of Finite-Lived Intangible Assets and Liabilities, Future Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets and Liabilities, Future Amortization Expense [Table Text Block] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Parent Company Parent Company [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Cash distributions Tax refund from parent company Tax Refund From Parent Tax Refund From Parent Tax payments to parent company Income Tax Payments, To Parent By Reporting Entity Income Tax Payments, To Parent By Reporting Entity Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Pronouncements Description of New Accounting Pronouncements Not yet Adopted [Text Block] Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Pension Plans, Defined Benefit Pension Plans, Defined Benefit [Member] Other Postretirement Benefit Plans, Defined Benefit Other Postretirement Benefit Plans, Defined Benefit [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Amortization of net loss Defined Benefit Plan, Amortization of Net Gains (Losses) Net cost recognized Defined Benefit Plan, Net Periodic Benefit Cost Discretionary contribution by Company Defined Benefit Plan, Contributions by Employer Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Consolidated Statements of Changes in Equity [Abstract] Consolidated Statements of Changes in Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Members Equity Members Equity [Member] Member's equity. Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) [Member] Increase (Decrease) in Member's Equity [Roll Forward] Increase (Decrease) In Members Equity [Roll Forward] [Roll Forward] Increase (Decrease) In Members Equity [Roll Forward] [Roll Forward] Balance Cash distributions to Parent Comprehensive income, net of tax Balance OCI Parenthetical [Abstract] OCI Parenthetical [Abstract] Change in amortization of accumulated actuarial losses, net of tax benefit Change In Unrecognized Prior Service Credit And Actuarial Losses Tax Benefit (Expense) The net tax benefit (expense) resulting from the adjustment out of other comprehensive income for prior service costs and actual losses recognized as a component of net period benefit cost during the period. Change in fuel hedge mark-to-market, net of tax expense/(benefit) Fuel Interest Hedge Mark To Market Tax Benefit (Expense) The net tax benefit (expense) resulting from the change in accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges, net of tax effect. Schedule of Guarantor Obligations Schedule of Guarantor Obligations [Table Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivative Instrument Risk [Axis] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] Derivative Contract Type [Domain] Fuel Contracts Fuel Contracts [Member] Fuel Contracts [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Current Assets Other Current Assets [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivatives, net Derivative Asset, Fair Value, Net Derivatives, gross Derivative Asset, Fair Value, Gross Asset Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Fuel Expense Fuel Expense [Member] Fuel Expense [Member] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Domain] Other Comprehensive Income Location [Domain] Other Comprehensive Income (Loss) Other Comprehensive Income (Loss) [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Amount of Gain or (Loss) Recognized in Other Comprehensive Income (OCI) on Derivatives (Effective Portion) Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Amount of Gain or (Loss) Recognized from AOCL into Income (Effective Portion) Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Amount of Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing) Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net Pre-tax hedge instrument gains estimated to be reclassified from accumulated other comprehensive loss into earnings Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Northern Sante Fe Corporation Northern Sante Fe Corporation [Member] Northern Sante Fe Corporation [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Acquired remaining outstanding shares, percentage Business Combination, Step Acquisition, Remaining Equity Interest Acquired, Percentage In a business combination achieved in stages, this element represents the percentage aquired of the remaining equity interest in the acquiree not already owned. Accounting Policies and Interim Results Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Parties to Contractual Arrangement [Axis] Parties to Contractual Arrangement [Axis] Parties to Contractual Arrangement [Domain] Parties to Contractual Arrangement [Domain] Reporting Entity Reporting Entity [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Equipment Equipment [Member] Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Future minimum lease payments Operating Leases, Future Minimum Payments Due Current Liabilities [Member] Current Liabilities [Member] Current Liabilities [Member] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Cash Equivalents Cash Equivalents [Member] Commercial Paper, Bank Time Deposits, and Money Market Funds Commercial Paper, Bank Time Deposits, and Money Market Funds [Member] Commercial Paper, Bank Time Deposits, and Money Market Funds [Member] Subsidiaries Subsidiaries [Member] BNSF Insurance Company BNSF Insurance Company [Member] BNSF Insurance Company [Member] Unasserted Claim Unasserted Claim [Member] Personal Injury Personal Injury [Member] Personal Injury [Member] Asbestos and Personal Injury [Abstract] Loss Contingency, Estimate [Abstract] Percent of future unasserted asbestos claims to be filed within the next ten years Percent of Future Unasserted Asbestos Claims To be Filed Within the Next Ten Years Percent of Future Unasserted Asbestos Claims To be Filed Within the Next Ten Years Percent of future unasserted asbestos claims to be filed within the next fifteen years Percent of Future Unasserted Asbestos Claims to be Filed Within the Next Fifteen Years Percent of Future Unasserted Asbestos Claims to be Filed Within the Next Fifteen Years Percent of future unasserted asbestos claims to be filed within the next twenty-five years Percent of Future Unasserted Asbestos Claims to be Filed Within the Next Twenty-five Years Percent of Future Unasserted Asbestos Claims to be Filed Within the Next Twenty-five Years Length in years for 60 percent of future unasserted asbestos claims to be filed Length in Years for 60 Percent of Future Unasserted Asbestos Claims to be Filed Length in Years for 60% of Future Unasserted Asbestos Claims to be Filed Length in years for 80 percent of future unasserted asbestos claims to be filed Length in Years for 80 Percent of Future Unasserted Asbestos Claims to be Filed Length in Years for 80 Percent of Future Unasserted Asbestos Claims to be Filed Length in years for 95 percent of future unasserted claims to be filed Length in Years for 95 Percent of Future Unasserted Claims to be Filed Length in Years for 95 Percent of Future Unasserted Claims to be Filed Accrued obligations for asbestos and other personal injury matters, current liabilities Loss Contingency, Accrual Carrying Value, Current Future costs to settle personal injury claims, minimum Future costs to settle personal injury claims, maximum Loss Contingency Accrual [Roll Forward] Loss Contingency Accrual [Roll Forward] Beginning balance Loss Contingency Accrual, at Carrying Value Accruals Loss Contingency Accrual, Carrying Value, Provision Payments Loss Contingency Accrual, Carrying Value, Payments Ending balance Cash and Cash Equivalents [Abstract] Cash and Cash Equivalents [Abstract] Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Corporate Debt Securities Corporate Debt Securities [Member] Junior Subordinated Debt Junior Subordinated Debt [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Three Point Zero Five Percent Debentures Due March 15, 2022 Three Point Zero Five Percent Debentures Due March 15, 2022 [Member] Three Point Zero Five Percent Debentures Due March 15, 2022 [Member] Four Point Four Zero Percent Debentures Due March 15, 2042 Four Point Four Zero Percent Debentures Due March 15, 2042 [Member] Four Point Four Zero Percent Debentures Due March 15, 2042 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Debentures issued amount Debt Instrument, Face Amount Debentures interest rate Debt Instrument, Interest Rate, Stated Percentage Subordintaed notes related to financial covenants Debt Instrument, Covenant Debt Certain issued and outstanding junior subordinated notes pertaining to certain financial covenants. Debt, fair value Long-term Debt, Fair Value Debt, book value Long-term Debt Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Business Segments [Axis] Business Segments [Axis] Segment [Domain] Segment [Domain] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Amortized intangible assets, gross carrying amount Finite-Lived Intangible Assets, Gross Amortized intangible assets, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Amortized intangible liabilities, gross carrying amount Finite-Lived Intangible Liabilities, Gross Amount before amortization of liabilities, excluding financial liabilities, lacking physical substance with a finite life. Amortized intangible liabilities, accumulated amortization Finite-Lived Intangible Liabilities, Accumulated Amortization Finite-Lived Intangible Liabilities, Accumulated Amortization Amortization of Intangible Assets Amortization of Intangible Assets Amortization of Intangible Liabilities Amortization of Intangible Liabilities Amortization of Intangible Liabilities Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Amortization of intangible assets, Remainder of 2012 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year Amortization of intangible liabilities, Remainder of 2012 Finite-Lived Intangible Liabilities, Amortization Expense, Remainder of Fiscal Year Finite-Lived Intangible Liabilities, Amortization Expense, Remainder of Fiscal Year Amortization of intangible assets, 2013 Finite-Lived Intangible Assets, Amortization Expense, Year Two Amortization of intangible liabilities, 2013 Finite-Lived Intangible Liabilities, Amortization Expense, Year Two Finite-Lived Intangible Liabilities, Amortization Expense, Year Two Amortization of intangible assets, 2014 Finite-Lived Intangible Assets, Amortization Expense, Year Three Amortization of intangible liabilities, 2014 Finite-Lived Intangible Liabilities, Amortization Expense, Year Three Finite-Lived Intangible Liabilities, Amortization Expense, Year Three Amortization of intangible assets, 2015 Finite-Lived Intangible Assets, Amortization Expense, Year Four Amortization of intangible liabilities, 2015 Finite-Lived Intangible Liabilities, Amortization Expense, Year Four Finite-Lived Intangible Liabilities, Amortization Expense, Year Four Amortization of intangible assets, 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Five Amortization of intangible liabilities, 2016 Finite-Lived Intangible Liabilities, Amortization Expense, Year Five Finite-Lived Intangible Liabilities, Amortization Expense, Year Five Other Assets Other Asset, Investment in Variable Interest Entity [Text Block] Other Asset, Investment in Variable Interest Entity [Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Company limited partner holding interest, percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage General partner holding interest, percentage Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Unconsolidated Partnership, assets Variable Interest Entity, Assets Variable Interest Entity, Assets Unamortized investment balance classified as Other Assets Variable Interest Entity, Nonconsolidated, Unamortized Investment Balance Variable Interest Entity, Nonconsolidated, Unamortized Investment Balance Remaining commitments classified as Other Liabilities Other Commitment Maximum exposure to loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Remaining commitments due at the end of 2012 Other Commitment, Due in Next Twelve Months Remaining commitments due at the end of 2013 Other Commitment, Due in Second Year Schedule of Loss Contingencies by Contingency Schedule of Loss Contingencies by Contingency [Table Text Block] Accrued Obligations for Environmental Matters Accrual for Environmental Loss Contingencies [Table Text Block] Accrual for Environmental Loss Contingencies [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block] Unrecognized prior service credit and actuarial losses, net of tax (see Note 8) Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Fuel hedge mark-to-market, net of tax (see Note 2) Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Accumulated other comprehensive loss of equity method investees Accumulated Other Comprehensive Income (Loss) Equity Method Investees, Net of Tax Accumulated Other Comprehensive Income (Loss) Equity Method Investees, Net of Tax Total accumulated other comprehensive loss Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Cost of Fuel [Member] Cost of Fuel [Member] Cost of Fuel [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Operating Expense [Member] Operating Expense [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Fuel costs percent of total operating costs Concentration Risk, Percentage Percent of past three years fuel consumption covered by derivatives Percent Of Past Three Years Fuel Consumption Covered By Derivatives Percent Of Past Three Years Fuel Consumption Covered By Derivatives Number of gallons of fuel covered by fuel-derivative agreements Number of Gallons of Fuel Covered by Fuel-derivative Agreements Number of Gallons of Fuel Covered by Fuel-derivative Agreements Net asset exposure to counterparty credit risk Maximum Potential Future Exposure on Credit Risk Derivatives Other Intangible Assets and Liabilities Goodwill And Other Intangible Assets and Liabilities [Text Block] Goodwill And Other Intangible Assets and Liabilities [Text Block]