Supplemental Financial Information - Other Non-Current Liabilities (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Other Liabilities, Noncurrent [Abstract]
Postretirement obligation	$ 143		$ 138
Non-current lease-related obligations	202		290
Other deferred compensation	167		163
Deferred gains from sale and leaseback of aircraft	57		65
Other	52		70
Other noncurrent liabilities	658		771
Interest rate derivatives | Other Noncurrent Liabilities
Other Liabilities, Noncurrent [Abstract]
Liability derivative contracts, net	$ 37	[1]	$ 45	[1]

[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.