Quarterly report pursuant to Section 13 or 15(d)

EMPLOYEE BENEFIT PLANS - Additional Information (Detail)

EMPLOYEE BENEFIT PLANS - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
9 Months Ended 9 Months Ended
Dec. 31, 2012
Sep. 30, 2013
Defined Benefit Pension Plan
Sep. 30, 2013
Defined Benefit Postretirement Medical Benefit Plan
Sep. 30, 2012
Represented by Teamsters [Member]
Sep. 30, 2012
Multiemployer Plans, Pension [Member]
Sep. 30, 2013
Multiemployer Plans, Pension [Member]
Defined Benefit Plan Disclosure [Line Items]            
Amount contributed to company- sponsored benefit plans   $ 76 $ 82      
Estimated future employer contributions to defined benefit plan, current fiscal year   24 29      
Number of employees under a national master agreement and various supplemental agreements with local unions affiliated with Teamsters 249,000          
Number of pilots under a collective bargaining agreement with the Independent Pilots Association 2,600          
Majority of ground mechanics not employed under agreements 3,100          
Multiemployer Plan, Number of Employees Covered       10,200    
Multiemployer Plans, Number of Beneficiary Groups         2  
Multiemployer Plans, Withdrawal Obligation         2,162  
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate         4.25%  
Multiemployer Plans, Payment Term         50 years  
Multiemployer Plans, Withdrawal Obligation, Present Value         $ 896 $ 808