Quarterly report pursuant to Section 13 or 15(d)

EMPLOYEE BENEFIT PLANS - Additional Information (Detail)

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EMPLOYEE BENEFIT PLANS - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Dec. 31, 2013
Pilots
Ground_Mechanics
Employees
Mar. 31, 2014
Defined Benefit Pension Plan
Mar. 31, 2013
Defined Benefit Postretirement Medical Benefit Plan
Mar. 31, 2014
Multiemployer Plans, Pension [Member]
Dec. 31, 2013
Multiemployer Plans, Pension [Member]
Defined Benefit Plan Disclosure [Line Items]          
Amount contributed to company- sponsored benefit plans   $ 25 $ 31    
Estimated future employer contributions to defined benefit plan, current fiscal year   78 69    
Number of employees under a national master agreement and various supplemental agreements with local unions affiliated with Teamsters 253,000        
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 Plans, Withdrawal Obligation, Present Value       882 884
Multi-employer Plans, Withdrawal Obligation, Fair Value Disclosure       $ 782 $ 783