Supplemental Financial Information - Accounts Payable (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Supplemental Financial Information - Accounts Payable [Abstract]
Accounts payable trade	$ 170	$ 123
Salaries payable	168	160
Tax withholdings payable	234	163
Aircraft Maintenance Payable	163	314
Fuel Payable	68	85
Other payables	331	358
Accounts Payable, Current	$ 1,134	$ 1,203