EMPLOYEE BENEFIT PLANS - Additional Information (Detail) (USD $) In Millions, unless otherwise specified		9 Months Ended			9 Months Ended
	Dec. 31, 2012 Employees Pilots Ground_Mechanics	Sep. 30, 2013 Defined Benefit Pension Plan	Sep. 30, 2013 Defined Benefit Postretirement Medical Benefit Plan	Sep. 30, 2012 Represented by Teamsters [Member] Employees	Sep. 30, 2012 Multiemployer Plans, Pension [Member] Group	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