Supplemental Financial Information - Accrued Liabilities (Details) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
ProfitSharing and savings plans		$ 384	$ 655
Aircraft and other lease related obligations		64	74
Vacation pay		317	309
Accrued union bonuses		213	329
Health		88	86
Workers compensation		188	187
Property and income taxes		140	62
Other		210	246
Accrued liabilities		1,869	2,591
Fuel derivatives | Accrued Liabilities
Accrued Liabilities, Current [Abstract]
Derivative contracts	[1]	$ 265	$ 643

[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.