Supplemental Financial Information - Accounts Payable (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts Payable [Abstract]
Accounts payable trade	$ 156	$ 111
Salaries payable	287	201
Taxes payable excluding income taxes	200	49
Aircraft maintenance payable	42	95
Fuel payable	170	66
Other payable	427	409
Accounts payable	$ 1,282	$ 931