CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Operating Revenues
Total Operating Revenues	$ 1,636.0	$ 1,876.0
Costs and Expenses, Total	1,957.0	1,851.0
Wages and benefits	612.0	557.0
Variable incentive pay	7.0	35.0
Aircraft fuel, including hedging gains and losses	384.0	420.0
Aircraft maintenance	115.0	120.0
Aircraft rent	81.0	83.0
Landing fees and other rentals	131.0	132.0
Contracted services	72.0	72.0
Selling expenses	55.0	72.0
Depreciation and amortization	108.0	106.0
Food and beverage service	49.0	49.0
Third-party regional carrier expense	37.0	41.0
Other	143.0	138.0
Special items - merger-related costs	3.0	26.0
Special items—other		0.0
Operating Income (Loss)	(321.0)	25.0
Nonoperating Income (Expense)
Interest income	9.0	9.0
Interest capitalized	3.0	4.0
Other—net	5.0	(10.0)
Nonoperating Income (Expense) Total	4.0	(19.0)
Income (Loss) Before Income Tax	(317.0)	6.0
Income tax (benefit) expense	(85.0)	2.0
Net Income (Loss)	$ (232.0)	$ 4.0
Basic Earnings Per Share (usd per share)	$ (1.89)	$ 0.03
Diluted Earnings Per Share (usd per share)	$ (1.87)	$ 0.03
Shares used for computation:
Basic shares (shares)	122,818	123,291
Diluted shares (shares)	124,123	123,915
Special items - Impairment charges and other	$ 160.0	$ 0.0
Increase (Decrease) in Contract with Customer, Liability	210.0	328.0
Interest Costs Incurred	13.0	22.0
Passenger Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	1,481.0	1,716.0
Passenger Revenue [Member] \| Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	1,481.0	1,716.0
Mileage Plan Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	261.0	263.0
Mileage Plan Revenue [Member] \| Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	152.0	153.0
Mileage Plan Revenue [Member] \| Mileage plan other revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	109.0	110.0
Cargo and Other Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	46.0	50.0
Cargo and Other Revenue [Member] \| Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 46.0	$ 50.0

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