Supplemental Financial Information - Other Assets (Details) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Other Assets [Abstract]
Asset derivative contracts, net		$ 1	$ 13
Intangible assets	[1]	474	363
Non-current investments		40	35
Other		134	123
Other assets		649	534
Accrued Liabilities | Fuel derivatives
Other Assets [Abstract]
Asset derivative contracts, net	[2]	0	0
Other Assets | Interest rate derivatives
Other Assets [Abstract]
Asset derivative contracts, net	[2]	$ 1	$ 13

[1] Intangible assets primarily consist of acquired leasehold rights to certain airport owned gates at Chicago’s Midway International Airport, takeoff and landing slots (a “slot” is the right of an air carrier, pursuant to regulations of the Federal Aviation Administration (“FAA”), to operate a takeoff or landing at a specific time at certain airports) at certain domestic slot-controlled airports, and certain intangible assets recognized from the AirTran acquisition. The increase in Intangible assets during 2015 was primarily due to the acquisition of two additional airport gate rights at Dallas Love Field, which were subleased from United Airlines. The purchase price paid for these airport gate rights was included as a component of Capital expenditures in the accompanying unaudited Condensed Consolidated Statement of Cash Flows.

[2] The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the unaudited Condensed Consolidated Balance Sheet in Note 5.