Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Feb. 28, 2021 aircraft
Summary Of Significant Accounting Policies [Line Items]
Expiration period for refundable tickets	1 year
Number of operating segments | segment	1
Revenue	$ 24,634	$ 15,355	$ 43,259
Period over which miles are expected to be redeemed	two years
Senior secured notes	$ 6,800
Carrying value of computer software	499	548
Impairment, long-lived asset	97	94	81
Amortization expense	49	55	60
Projected amortization expense in 2022	40
Projected amortization expense in 2023	37
Projected amortization expense in 2024	32
Projected amortization expense in 2025	28
Projected amortization expense in 2026	18
Advertising expense	$ 99	87	212
Boeing 777-200/200ER
Summary Of Significant Accounting Policies [Line Items]
Number of aircraft temporarily removed | aircraft				52
Minimum
Summary Of Significant Accounting Policies [Line Items]
Frequent flier program expiration period	1 year
Maximum
Summary Of Significant Accounting Policies [Line Items]
Frequent flier program expiration period	8 years
Computer software
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense	$ 182	172	135
Advance Ticket Sales
Summary Of Significant Accounting Policies [Line Items]
Expiration period for advance ticket sales	12 months
Contract liabilities	$ 3,200
Revenue recognized	1,800	3,000	3,400
Ancillary Fees Recorded within Passenger Revenues
Summary Of Significant Accounting Policies [Line Items]
Revenue	2,200	1,300	3,600
Other Operating Revenue
Summary Of Significant Accounting Policies [Line Items]
Revenue	2,088	1,902	2,455
Other Operating Revenue | Chase and Other Partner Agreements
Summary Of Significant Accounting Policies [Line Items]
Revenue	$ 1,800	$ 1,700	$ 2,000