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
Sep. 30, 2012
Dec. 31, 2011
Sep. 30, 2012
Defined Benefit Pension Plan
Sep. 30, 2012
Defined Benefit Postretirement Medical Benefit Plan
Defined Benefit Plan Disclosure [Line Items]        
Amount contributed to company- sponsored benefit plans     $ 418 $ 446
Estimated future employer contributions to defined benefit plan, current fiscal year     6 25
Number of employees under a national master agreement and various supplemental agreements with local unions affiliated with Teamsters   245,000    
Number of pilots under a collective bargaining agreement with the Independent Pilots Association   2,700    
Majority of ground mechanics not employed under agreements   3,200    
Number of Employees in Pension Plan 10,200      
Withdrawal Liability Gross Payment Obligation 2,162      
Withdrawal Liability Term 50 years      
Discount Rate for Present Value of Withdrawal Liability 4.25%      
Multiemployer Plan, Withdrawal Obligation $ 896