Supplemental Financial Information - Other Non-Current Liabilities (Details) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Other Liabilities, Noncurrent [Abstract]
Postretirement obligation		$ 211	$ 201
Non-current lease-related obligations		145	165
Other deferred compensation		190	179
Deferred gains from sale and leaseback of aircraft		38	43
Other		80	98
Other noncurrent liabilities		681	760
Other Noncurrent Liabilities
Other Liabilities, Noncurrent [Abstract]
Derivative contracts		17	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]	$ 44	$ 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.