CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,658	$ 1,527	$ 4,339	$ 2,324
Operating Expenses
Wages and benefits	639	510	1,245	1,003
Variable incentive pay	56	34	92	67
PSPGrantRecognized	0	(503)	0	(914)
Aircraft fuel, including hedging gains and losses	776	274	1,123	477
Aircraft maintenance	104	102	239	183
Aircraft rent	73	62	146	124
Landing fees and other rentals	136	144	274	273
Contracted services	82	54	160	105
Selling expenses	78	41	136	74
Depreciation and amortization	104	98	206	195
Food and beverage service	50	35	91	58
Third-party regional carrier expense	50	37	92	67
Other	177	117	329	222
Special items - Impairment charges and other	146	(4)	221	14
Restructuring Charges	0	(23)	0	(12)
Operating Expenses	2,471	978	4,354	1,936
Costs and Expenses, Total	2,471	978	4,354	1,936
Operating Income (Loss)	187	549	(15)	388
Nonoperating Income (Expense)
Interest income	11	6	18	13
Interest expense	(26)	(39)	(53)	(71)
Interest capitalized	3	3	5	6
Other—net	10	9	24	19
Nonoperating Income (Expense) Total	(2)	(21)	(6)	(33)
Income (Loss) Before Income Tax	185	528	(21)	355
Income tax (benefit) expense	46	131	(17)	89
Net Income (Loss)	$ 139	$ 397	$ (4)	$ 266
Basic Earnings Per Share (usd per share)	$ 1.10	$ 3.18	$ (0.03)	$ 2.13
Diluted Earnings Per Share (usd per share)	$ 1.09	$ 3.13	$ (0.03)	$ 2.10
Shares used for computation:
Basic shares (shares)	126,543,000	124,977,000	126,265,000	124,640,000
Diluted shares (shares)	127,795,000	126,825,000	126,265,000	126,388,000
Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,418	$ 1,352	$ 3,929	$ 2,011
Mileage plan other revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	175	118	287	212
Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	65	57	123	101
Passenger Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	2,418	1,352	3,929	2,011
Passenger Revenue [Member] | Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	2,418	1,352	3,929	2,011
Mileage Plan Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	422	272	722	450
Mileage Plan Revenue [Member] | Mileage plan other revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	175	118	287	212
Cargo and Other Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	65	57	123	101
Cargo and Other Revenue [Member] | Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 65	$ 57	$ 123	$ 101