Supplemental Financial Information - Other Non-Current Liabilities (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Other Liabilities, Noncurrent [Abstract]
Postretirement obligation		$ 206	$ 201
Non-current lease-related obligations		155	165
Other deferred compensation		168	179
Deferred gains from sale and leaseback of aircraft		40	43
Other		88	98
Other noncurrent liabilities		703	760
Other Noncurrent Liabilities
Other Liabilities, Noncurrent [Abstract]
Derivative contracts		46	74
Fuel derivatives | Other Noncurrent Liabilities
Other Liabilities, Noncurrent [Abstract]
Derivative contracts	[1]	0	25
Interest rate derivatives | Other Noncurrent Liabilities
Other Liabilities, Noncurrent [Abstract]
Derivative contracts	[1]	$ 46	$ 49

[1] 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.