CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE OPERATIONS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ (214)	$ 262	$ (446)	$ 266
Related to marketable securities:
Unrealized holding gain (loss) arising during the period	31	13	30	27
Reclassification of (gain) loss into Other - net nonoperating income (expense)	(6)	0	(9)	2
Income tax effect	(6)	(3)	(5)	(7)
Total	19	10	16	22
Related to employee benefit plans:
Reclassification of net pension expense into Wages and benefits and Other - net nonoperating income (expense)	8	8	15	16
Income tax effect	(2)	(2)	(4)	(4)
Total	6	6	11	12
Related to interest rate derivative instruments:
Unrealized holding gain (loss) arising during the period	(2)	(7)	(27)	(12)
Reclassification of loss into Aircraft rent	0	0	1	1
Income tax effect	1	2	6	3
Total	(1)	(5)	(20)	(8)
Other Comprehensive Income (Loss)	24	11	7	26
Comprehensive Income (Loss)	$ (190)	$ 273	$ (439)	$ 292