Accounting Policies [Abstract] Equity [Abstract] Class of Treasury Stock [Table] Class of Treasury Stock [Table] Equity, Class of Treasury Stock [Axis] Class of Treasury Stock [Domain] Common Stock [Member] Stock Repurchase Program [Axis] Stock Repurchase Program [Axis] Stock Repurchase Program [Member] Stock Repurchase Programs [Member] Stock Repurchase Program [Member] June 2011 Stock Repurchase Program [Member] June 2011 Stock Repurchase Program [Member] June 2010/June 2011 Stock Repurchase Programs [Member] June 2010/June 2011 Stock Repurchase Programs [Member] June 2010 Stock Repurchase Program [Member] June 2010 Stock Repurchase Program [Member] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Treasury Stock, Shares, Acquired Treasury Stock, Shares, Acquired Treasury Stock, Value, Acquired, Cost Method Treasury Stock, Value, Acquired, Cost Method Treasury Stock Acquired, Average Cost Per Share Treasury Stock Acquired, Average Cost Per Share Debt Disclosure [Abstract] Long-term Debt Long-term Debt [Text Block] Segment Reporting [Abstract] Operating Segment Information Segment Reporting Disclosure [Text Block] Other Assets [Abstract] Schedule of Other Assets, Noncurrent [Table Text Block] Schedule of Other Assets, Noncurrent [Table Text Block] Fair Value Disclosures [Abstract] Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value of Financial Instruments, Policy [Policy Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Reconciliation of Assets from Segment to Consolidated [Table Text Block] Reconciliation of Assets from Segment to Consolidated [Table Text Block] Treasury Stock [Text Block] Treasury Stock [Text Block] CONSTRUCTION OF TERMINAL 6 AT LAX [Abstract] CONSTRUCTION OF TERMINAL 6 AT LAX [Abstract] Schedule of Other Assets [Table] Schedule of Other Assets [Table] Schedule of Other Assets [Table] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Domain] Construction in Progress [Member] Other Assets [Line Items] Other Assets [Line Items] LAX airport project companys responsibility amount before reimbursement LAX airport project companys responsibility amount before reimbursement LAX airport project companys responsibility amount before reimbursement LAX airport project estimated total cost LAX airport project estimated total cost LAX airport project estimated total cost LAX airport project companys responsibility amount after reimbursement LAX airport project companys responsibility amount after reimbursement LAX airport project companys responsibility amount after reimbursement LAX airport project portion included in property and equipment LAX airport project portion included in property and equipment LAX airport project portion included in property and equipment LAX airport project reimbursement and credits in other long-term liabilities LAX Airport Project Reimbursement and Credits in Other Long-term Liabilities LAX Airport Project Reimbursement and Credits in Other Long-term Liabilities Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Statement, Business Segments [Axis] Statement, Business Segments [Axis] Segment [Domain] Segment [Domain] Operating Segments [Member] Operating Segments [Member] Reportable Segment [Member] Reportable Segment [Member] Alaska Air [Member] Alaska Air Segment [Member] Horizon [Member] Horizon Segment [Member] Alaska mainline excluding fuel [Member] Alaska mainline excluding fuel [Member] Alaska mainline fuel [Member] Alaska mainline fuel [Member] Alaska regional [Domain] Alaska regional All Other Segments [Member] All Other Segments [Member] Significant Reconciling Items [Member] Significant Reconciling Items [Member] Unallocated Amount to Segment [Member] Unallocated Amount to Segment [Member] Intersegment Elimination [Member] Intersegment Elimination [Member] Corporate Elimination [Member] Corporate Elimination [Member] Parent Company Results Eliminated In Consolidation [Member] Parent Company Results Eliminated In Consolidation [Member] Mainline [Member] Aircraft Type [Axis] Aircraft Type [Axis] Aircraft Type [Domain] Aircraft Type [Domain] CRJ 700 [Member] CRJ 700 [Member] CRJ-700 [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Segment Reporting Information, Profit (Loss) [Abstract] Passenger Revenue, Mainline Passenger Revenue, Mainline Passenger Revenue, Regional Passenger Revenue, Regional Passenger Revenue Passenger Revenue Other revenue and freight and mail revenue Other revenue and freight and mail revenue Other revenue including freight and mail revene Revenue, Net Revenue, Net Operating Expenses Operating Expenses Nonoperating Income (Expense) Nonoperating Income (Expense) Income before income tax Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Assets Assets Capacity Sold Under CPA Percent Capacity Sold Under CPA Percent Capacity Sold Under CPA Percent Fleet transition costs Restructuring, Settlement and Impairment Provisions MILEAGE PLAN [Abstract] MILEAGE PLAN [Abstract] Mileage Plan Liabilities [Table Text Block] Mileage Plan Liabilities [Table Text Block] Mileage Plan Liabilities [Table Text Block] Mileage Plan Revenue [Table Text Block] Mileage Plan Revenue [Table Text Block] Mileage Plan Revenue [Table Text Block] CONSTRUCTION OF TERMINAL 6 AT LAX [Text Block] CONSTRUCTION OF TERMINAL 6 AT LAX [Text Block] CONSTRUCTION OF TERMINAL 6 AT LAX [Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Range [Axis] Range [Domain] Minimum [Member] Maximum [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Fixed rate notes payable due through 2024 [Member] Fixed rate notes payable due through 2024 Variable rate notes payable due through 2024 [Member] Variable rate notes payable due through 2024 [Member] B737-800 [Member] B737-800 [Member] Q400 [Member] Q400 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term Debt Long-term Debt Less current portion Long-term Debt, Current Maturities Long-term debt, net of current portion Long-term Debt, Excluding Current Maturities Scheduled debt payments Debt Instrument, Periodic Payment Number of Debt Agreements Debt Agreements, Number Debt Agreements, Number Prepayment of debt balance Prepayments of Long Term Debt Prepaid long term debt Proceeds from Issuance of Long-term Debt Proceeds from Issuance of Long-term Debt Number of Aircraft Delivered Number of Aircraft Delivered Prepayment of Long Term Debt, Expected Prepayment Amount Prepayment of Long Term Debt, Expected Prepayment Amount Prepayment of Long Term Debt, Expected Prepayment Amount Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 2 [Member] Credit Derivatives by Contract Type [Axis] Credit Derivatives Contract Type [Domain] Interest Rate Swap [Member] Call Option [Member] Commodity Option [Member] Swap [Member] Derivative, by Nature [Axis] Derivative, by Nature [Axis] Derivative, Name [Domain] Derivative, Name [Domain] Derivative [Line Items] Derivative [Line Items] Price Risk Derivatives, at Fair Value, Net Price Risk Derivatives, at Fair Value, Net Derivative Premiums Capitalized Derivative Premiums Capitalized Derivative Premiums Capitalized Capital Leased Assets, Number of B737-800 Aircraft Capital Leased Assets, Number of Units Interest Rate Cash Flow Hedge Liability at Fair Value Interest Rate Cash Flow Hedge Liability at Fair Value Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Restructuring, Settlement and Impairment Provisions [Abstract] Fleet Transition Restructuring and Related Activities Disclosure [Text Block] Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Information by Category of Debt Security [Axis] Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments [Domain] Available-for-sale Securities [Member] Debt Security [Axis] Major Types of Debt Securities [Domain] Asset-backed Securities [Member] Schedule of Available-for-sale Securities, Major Types of Debt and Equity Securities [Axis] Schedule of Available-for-sale Securities, Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] US Treasury and Government [Member] Asset-backed Securities [Member] Other Debt Obligations [Member] Other Debt Obligations [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses Available-for-sale Securities, Amortized Cost Basis Available-for-sale Securities, Amortized Cost Basis Available-for-sale Securities, Fair Value Disclosure Available-for-sale Securities, Fair Value Disclosure Compensation and Retirement Disclosure [Abstract] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Available-for-sale Securities [Table Text Block] Available-for-sale Securities [Table Text Block] Available for Sale Securities Gross Unrealized Gains and Losses [Table Text Block] Available-for-sale Securities Gross Unrealized Gains and Losses [Table Text Block] Fair Value of Long Term Debt [Table Text Block] Fair Value of Long Term Debt [Table Text Block] Fair Value of Long Term Debt [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Qualified defined benefit [Member] Qualified defined benefit [Member] Nonqualified defined benefit [Member] Nonqualified defined benefit [Member] Post retirement medical benefits [Member] Post retirement medical benefits [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 asets Defined Benefit Plan, Expected Return on Plan Assets Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Actuarial loss Defined Benefit Plan, Actuarial Net (Gains) Losses Net pension expense Defined Benefit Plan, Net Periodic Benefit Cost Defined Benefit Plan, Contributions by Employer Defined Benefit Plan, Contributions by Employer Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair Value, Disclosure Item Amounts [Domain] Fair Value, Disclosure Item Amounts [Domain] Carrying (Reported) Amount, Fair Value Disclosure [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member] Estimate of Fair Value, Fair Value Disclosure [Member] Estimate of Fair Value, Fair Value Disclosure [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Notes Payable, Fair Value Disclosure Notes Payable, Fair Value Disclosure Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement, Scenario [Axis] Statement, Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Statement [Line Items] Statement [Line Items] ASSETS Assets [Abstract] Current Assets Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Marketable Securities, Current Total cash and marketable securities Total Cash And Marketable Securities The total of cash and cash equivalents and current marketable securities. Receivables - net Receivables, Net, Current Inventories and supplies - net Inventory, Net Deferred income taxes Deferred Tax Assets, Net, Current Fuel hedge contracts Derivative Instruments and Hedges, Assets Prepaid expenses and other current assets Prepaid Expense and Other Assets Total Current Assets Assets, Current Property and Equipment Property, Plant and Equipment, Net [Abstract] Aircraft and other flight equipment Flight Equipment, Gross Other property and equipment Property, Plant and Equipment, Other, Gross Deposits for future flight equipment Deposits on Flight Equipment Property and Equipment Total Property, Plant and Equipment, Gross Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total Property and Equipment - Net Property, Plant and Equipment, Net Fuel Hedge Contracts Derivative Instruments and Hedges, Noncurrent Other Assets Other Assets, Noncurrent Total Assets LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity [Abstract] Current Liabilities Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued aircraft rent Capital Lease Obligations, Current Accrued wages, vacation and payroll taxes Employee-related Liabilities, Current Other accrued liabilities Accrued Liabilities, Current Air traffic liability Deferred Air Traffic Revenue, Current Current portion of long-term debt Debt, Current Total Current Liabilities Liabilities, Current Other Liabilities and Credits Liabilities, Noncurrent [Abstract] Deferred income taxes Deferred Tax Liabilities, Noncurrent Deferred revenue Deferred Revenue Obligation for pension and postretirement medical benefits Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent Other liabilities Other Liabilities, Noncurrent Other Liabilities and Credits Totals Liabilities, Noncurrent Commitments and Contingencies Commitments and Contingencies Shareholders' Equity Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract] Preferred stock, $1 par value Authorized: 5,000,000 shares, none issued or outstanding Preferred Stock, Value, Issued Common stock, $1 par value Authorized: 100,000,000 shares, Issued: 2011 - 37,758,719 shares; 2010 - 37,010,140 shares Common Stock, Value, Issued Capital in excess of par value Additional Paid in Capital, Common Stock Treasury stock (common), at cost: 2011 - 2,113,247 shares; 2010 - 1,086,172 shares Treasury Stock, Value Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Shareholders' Equity Stockholders' Equity Attributable to Parent Total Liabilities and Shareholders' Equity Liabilities and Equity Share-based Compensation [Abstract] Stock Based Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Statement of Cash Flows [Abstract] Cash flows from 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 activites: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Fleet transition costs Restructuring Charges Depreciation and amortization Depreciation, Depletion and Amortization Stock-based Compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Increase in air traffic liability Increase (Decrease) in Air Traffic Liability Increase in other assets and liabilities – net Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Aircraft and aircraft purchase deposits Payments for Flight Equipment Other flight equipment Payments to Acquire Other Productive Assets Other property and equipment Payments to Acquire Other Property, Plant, and Equipment Total property and equipment additions Payments to Acquire Property, Plant, and Equipment Proceeds from disposition of assets Proceeds from Sale of Productive Assets Purchases of marketable securities Payments to Acquire Marketable Securities Sales and maturities of marketable securities Proceeds from Sale and Maturity of Marketable Securities Construction of Terminal 6 at LAX Payments for Construction in Process Restricted deposits and other Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from issuance of long-term debt Long-term debt payments Repayments of Long-term Debt Purchase of treasury stock Payments for Repurchase of Common Stock Proceeds and tax benefit from issuance of common stock Proceeds from Issuance of Common Stock Other financing activities Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net change in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of year Cash and cash equivalents at end of period Supplemental disclosure of cash paid during the period for: Supplemental Cash Flow Information [Abstract] Interest (net of amount capitalized) Interest Paid, Net Income taxes Income Taxes Paid, Net Relocation credit and assets constructed on account related to Terminal 6 at LAX Capital Expenditures Incurred but Not yet Paid Schedule Of Mileage Plan Liabilities [Table] Schedule Of Mileage Plan Liabilities [Table] Schedule Of Mileage Plan Liabilities [Table] Mileage Plan [Axis] Mileage Plan [Axis] Mileage Plan [Member] Mileage Plan [Member] Mileage Plan [Member]. Liabilities From Mileage Plan [Member] Liabilities From Mileage Plan [Member] Revenue From Mileage Plan [Member] Revenue From Mileage Plan [Member] Mileage Plan [Line Items] Mileage Plan [Line Items] Mileage Plan [Line Items] Accrued Liabilities, Current Deferred Air Traffic Revenue Noncurrent Other Liabilities, Noncurrent Liabilities Liabilities Other Revenue, Net Other Revenue, Net Total Operating Revenues 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] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Raw or into-plane fuel cost Fuel Costs, Gross of Hedging (Gains) or losses in value and settlements of fuel hedge contracts Gain (Loss) on Oil and Gas Hedging Activity Aircraft fuel expense Fuel Costs Payments for (Proceeds from) Hedge, Investing Activities Payments for (Proceeds from) Hedge, Investing Activities Restricted Investments Restricted Investments Other Assets, Misc, Noncurrent Other Assets, Miscellaneous, Noncurrent Other Assets, Noncurrent Report Date [Axis] Financial Statements Date [Domain] September 30, 2011 [Member] September 30, 2011 [Member] Future Period [Axis] Future Period [Axis] Future Period [Member] Future Period [Member] Third Quarter 2011 [Member] Third Quarter 2011 [Member] Fourth Quarter 2011 [Member] Fourth Quarter 2011 [Member] Remainder Of 2011 [Member] Remainder Of 2011 [Member] First Quarter 2012 [Member] First Quarter 2012 [Member] Second Quarter 2012 [Member] Second Quarter 2012 [Member] Third Quarter 2012 [Member] Third Quarter 2012 [Member] Fourth Quarter 2012 [Member] Fourth Quarter 2012 [Member] Full Year 2012 [Member] Full Year 2012 [Member] First Quarter 2013 [Member] First Quarter 2013 [Member] Second Quarter 2013 [Member] Second Quarter 2013 [Member] Third Quarter 2013 [Member] Third Quarter 2013 [Member] Fourth Quarter 2013 [Member] Fourth Quarter 2013 [Member] Full Year 2013 [Member] Full Year 2013 [Member] First Quarter 2014 [Member] First Quarter 2014 [Member] Second Quarter 2014 [Member] Second Quarter 2014 [Member] Third Quarter 2014 [Member] Third Quarter 2014 [Member] Full Year 2014 [Member] Full Year 2014 [Member] Swap [Member] Nonmonetary Notional Amount of Price Risk Derivatives Nonmonetary Notional Amount of Price Risk Derivatives Derivative, Nonmonetary Notional Amount, Price Per Barrel Derivative, Nonmonetary Notional Amount, Price Per Barrel Derivative Nonmonetary Notional Amount Premium Cost Per Barrel Derivative Nonmonetary Notional Amount Premium Cost Per Barrel Derivative Nonmonetary Notional Amount Premium Cost Per Barrel Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage Derivative, Nonmonetary Notional Amount, Estimated Price Per Gallon Derivative, Nonmonetary Notional Amount, Price Per Gallon Average jet fuel purchase price per gallon Derivative, Swap Type, Average Fixed Price Organization, Consolidation and Presentation of Financial Statements [Abstract] BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] EMPLOYEE BENEFIT PLANS Pension and Other Postretirement Benefits Disclosure [Text Block] Income Statement [Abstract] Operating Revenues Revenues [Abstract] Mainline Regional Total passenger revenue Freight and mail Cargo and Freight Revenue Other - net Operating Expenses Operating Expenses [Abstract] Wages and benefits Labor and Related Expense Variable incentive pay Other Labor-related Expenses Aircraft fuel, including hedging gains and losses Aircraft maintenance Aircraft Maintenance, Materials, and Repairs Aircraft rent Aircraft Rental Landing fees and other rentals Landing Fees and Other Rentals Contracted services Professional and Contract Services Expense Selling expenses Selling Expense Food and beverage service Food and Beverage, Cost of Sales Other Other Cost and Expense, Operating Total Operating Expenses Operating Income Operating Income (Loss) Nonoperating Income (Expense) Nonoperating Income (Expense) [Abstract] Interest income Investment Income, Interest Interest expense Interest Expense Interest capitalized Interest Costs, Capitalized During Period Other - net Other Nonoperating Income (Expense) Nonoperating Income (Expense) Total Income tax expense Income Tax Expense (Benefit) Net Income Basic Earnings Per Share: Earnings Per Share, Basic Diluted Earnings Per Share: Earnings Per Share, Diluted Shares used for computation: Earnings Per Share [Abstract] Basic Weighted Average Number of Shares Outstanding, Basic Diluted Weighted Average Number of Shares Outstanding, Diluted Mileage Plan Frequent Flyer Plan Disclosure [Text Block] Frequent Flyer Plan Disclosure [Text Block] Fair Value Disclosures [Text Block] Fair Value Disclosures [Text Block] Statement of Stockholders' Equity [Abstract] Statement, Equity Components [Axis] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Capital in Excess of Par Value Additional Paid-in Capital [Member] Treasury Stock, at Cost Treasury Stock [Member] Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss) [Member] Retained Earnings Retained Earnings [Member] Balances Balances (Shares) Common Stock, Shares, Outstanding Net income for the nine months ended September 30, 2011 Other Comprehensive Income (Loss), Tax [Abstract] Other Comprehensive Income (Loss), Tax [Abstract] Related to Marketable Securities: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract] Change in Fair Value Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Reclassification to Earnings Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax Income Tax Effect Other Comprehensive Income (Loss), Tax Marketable Securities, Net of Tax Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Related to Employee Benefit Plans Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax Income Tax Effect Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax Related to Employee Benefit Plans, Net of Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Related to Interest Rate Derivative Instruments: Derivative Instruments and Hedges, Assets [Abstract] Change in Fair Value Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax Income Tax Effect Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Effect Interest Rate Derivative Instruments, Net of Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Total Comprehensive Income Other Comprehensive Income (Loss), Net of Tax Purchase of Treasury Stock (Share) Stock Repurchased During Period, Shares Purchase of Treasury Stock Stock Repurchased During Period, Value Treasury Stock Issued Under Stock Plans (Share) Stock Issued During Period, Shares, Treasury Stock Reissued Treasury Stock Issued Under Stock Plans Stock Issued During Period, Value, Treasury Stock Reissued Stock Issued for Employee Stock Purchase Plan (Shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Stock Issued for Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Stock Issued Under Stock Plans (Shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock Issued Under Stock Plans Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Balances Balances (Shares) Commitments and Contingencies Disclosure [Abstract] Contingencies Commitments and Contingencies Disclosure [Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Other Assets Disclosure [Text Block] Other Assets Disclosure [Text Block] Restructuring and Related Activities [Abstract] Schedule of Restructuring and Related Costs [Table] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Disposal of Aircraft [Member] Disposal of Aircraft [Member] Restructuring Cost and Reserve [Axis] Type of Restructuring [Domain] Fleet Transition [Member] Fleet Transition [Member] Q200 [Member] Q200 aircraft [Member] Restructuring Cost and Reserve [Line Items] Number Of Aircraft Sold Number Of Aircraft Sold Number Of Aircraft Sold Number Of Aircraft To Be Sold Number Of Aircraft To Be Sold Number Of Aircraft To Be Sold Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Total stock based compensation [Domain] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Stock Compensation Plan [Member] Stock Compensation Plan [Member] Stock options [Member] Stock Options [Member] Restricted Stock [Member] Restricted Stock [Member] Stock Appreciation Rights (SARs) [Member] Stock Appreciation Rights (SARs) [Member] Restricted stock units [Member] Restricted Stock Units (RSUs) [Member] Performance share units [Member] Performance Stock Awards [Member] Performance Stock Awards [Member] Deferred stock awards [Member] Deferred Stock Awards [Member] Deferred Stock Awards [Member] Employee stock purchase plan [Member] Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Options, Grants in Period, Gross Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Options, Grants in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Compensation Cost Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Nonvested Awards, Total Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Equity Instruments Other than Options, Vested in Period, Total Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Options, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options, Outstanding, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options, Exercisable, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options, Exercisable, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value by Measurement Frequency [Axis] Fair Value by Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash and Cash Equivalents, Fair Value Disclosure Cash and Cash Equivalents, Fair Value Disclosure Assets, Fair Value Disclosure Assets, Fair Value Disclosure Marketable securities maturing in 2011 percentage Marketable securities maturing in 2011 percentage Marketable securities maturing in 2011 percentage Marketable securities maturing in 2012 percentage Marketable securities maturing in 2012 percentage Marketable securities maturing in 2012 percentage Marketable securities maturing after 2012 percentage Marketable securities maturing after 2012 percentage Marketable securities maturing after 2012 percentage Fair Value, Level 1 to level 2 Transfers, Amount Fair Value, Level 1 to level 2 Transfers, Amount Fair Value, Level 2 to level 1 Transfers, Amount Fair Value, Level 2 to level 1 Transfers, Amount Long-term Debt, Unclassified [Abstract] Line of Credit Facility [Table] Line of Credit Facility [Table] Line of Credit Facility [Axis] Line of Credit Facility [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Secured by aircraft [Member] Secured by aircraft [Member] Secured by other [Member] Secured by other [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Expiration Date Line of Credit Facility, Expiration Date Line of credit minumum asset requirement amount Line of Credit Facility Asset Restrictions Minumum Unrestricted Cash and Marketable Securities Required Line of credit minumum asset requirement amount Unrealized Gains in AOCL Available-for-sale Securities, Gross Unrealized Gains Unrealized Losses - Less Than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses Unrealized Losses - Greater Than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses Unrealized Losses - Total Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities Unrealized Losses - Net Unrealized Losses in AOCL Available-for-sale Securities, Gross Unrealized Losses Net Unrealized Gains/(Losses) in AOCL Available-for-sale Securities, Gross Unrealized Gain (Loss) Fair Value of Securities with Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Schedule of Price Risk Derivatives [Table Text Block] Schedule of Price Risk Derivatives [Table Text Block] Outstanding fuel hedge positions [Table Text Block] Outstanding fuel hedge positions [Table Text Block] Outstanding fuel hedge positions [Table Text Block] Schedule of Derivative Assets at Fair Value [Table Text Block] Schedule of Derivative Assets at Fair Value [Table Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document and Entity Information [Table] Document and Entity Information [Table] Document and Entity Information [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 Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 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 Public Float Entity Public Float Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred Stock, par value Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Treasury Stock (common) at cost Treasury Stock, Shares