CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating Revenues
Total Operating Revenues	$ 1,527	$ 421	$ 2,324	$ 2,057
Operating Expenses
Wages and benefits	510	472	1,003	1,084
Variable incentive pay	34	16	67	23
PSPGrantRecognized	(503)	362	(914)	362
Aircraft fuel, including hedging gains and losses	274	59	477	443
Aircraft maintenance	102	45	183	160
Aircraft rent	62	74	124	155
Landing fees and other rentals	144	83	273	214
Contracted services	54	30	105	102
Selling expenses	41	4	74	59
Depreciation and amortization	98	107	195	215
Food and beverage service	35	7	58	56
Third-party regional carrier expense	37	26	67	63
Other	117	78	222	221
Special items - Impairment charges and other	(4)	69	14	229
Restructuring Charges	(23)	0	(12)	0
Special items - merger-related costs	0	1	0	4
Costs and Expenses, Total	978	709	1,936	2,666
Operating Income (Loss)	549	(288)	388	(609)
Nonoperating Income (Expense)
Interest income	6	7	13	16
Interest Costs Incurred	(39)	(17)	(71)	(30)
Interest capitalized	3	1	6	4
Other—net	9	6	19	11
Nonoperating Income (Expense) Total	(21)	(3)	(33)	1
Income (Loss) Before Income Tax	528	(291)	355	(608)
Income tax (benefit) expense	131	(77)	89	(162)
Net Income (Loss)	$ 397	$ (214)	$ 266	$ (446)
Basic Earnings Per Share (usd per share)	$ 3.18	$ (1.74)	$ 2.13	$ (3.62)
Diluted Earnings Per Share (usd per share)	$ 3.13	$ (1.74)	$ 2.10	$ (3.62)
Shares used for computation:
Basic shares (shares)	124,977,000	123,296,000	124,640,000	123,058,000.000
Diluted shares (shares)	126,825,000	123,296,000	126,388,000	123,058,000.000
Passenger Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 1,352	$ 309	$ 2,011	$ 1,790
Passenger Revenue [Member] | Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	1,352	309	2,011	1,790
Mileage Plan Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	272	129	450	390
Mileage Plan Revenue [Member] | Mileage plan other revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	118	73	212	182
Cargo and Other Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	57	39	101	85
Cargo and Other Revenue [Member] | Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 57	$ 39	$ 101	$ 85