Supplemental Financial Information - Accrued Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Accrued Liabilities, Current [Abstract]
Profitsharing and savings plans	$ 391		$ 244
Aircraft and other lease related obligations	122		173
Vacation pay	287		278
Health	72		73
Workers compensation	162		161
Accrued Income Taxes, Current	313		3
Accrual for Taxes Other than Income Taxes, Current	65		62
Other	233		223
Accrued liabilities	1,645		1,229
Fuel derivatives | Accrued Liabilities
Accrued Liabilities, Current [Abstract]
Liability derivative contracts, net	$ 0	[1]	$ 12	[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.