Supplemental Financial Information - Other Assets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Other Assets [Abstract]
Asset derivative contracts, net	$ 183		$ 145
Intangible assets	372	[1]	166	[1]
Non-current investments	37		44
Other	180		175
Other assets	772		530
Accrued Liabilities | Fuel derivatives
Other Assets [Abstract]
Asset derivative contracts, net	0	[2]	0	[2]
Other Assets | Fuel derivatives
Other Assets [Abstract]
Asset derivative contracts, net	165	[2]	125	[2]
Other Assets | Interest rate derivatives
Other Assets [Abstract]
Asset derivative contracts, net	$ 18	[2]	$ 20	[2]

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjA0MWE5NjY1NTZhYzQ5OGZhZjhlYzAzMDFkNjI4NDhlfFRleHRTZWxlY3Rpb246MEJFQkI0MkYyN0MzREY5M0QyQTNBQTEyQTBDMTVFRTIM}

[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.