CONSOLIDATED STATEMENTS OF COMPREHENSIVE OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income	$ 769	$ 437	$ 960
Related to marketable securities:
Unrealized holding gains (losses) arising during the period	31	(14)	(4)
Reclassification of (gains) losses into Other-net non-operating income (expense)	(5)	8	1
Income tax benefit (expense)	(6)	2	1
Marketable securities, net of tax	20	(4)	(2)
Related to employee benefit plans:
Actuarial losses related to pension and other postretirement benefit plans	(71)	(34)	(123)
Reclassification of net pension expense into Wages and benefits and Other-net non-operating income	32	28	22
Income tax benefit (expense)	10	2	24
Employee benefit plans, net of tax	29	4	77
Related to interest rate derivative instruments:
Unrealized holding gains (losses) arising during the period	(13)	0	1
Reclassification of losses into Aircraft rent	3	3	5
Income tax benefit (expense)	2	(1)	(2)
Interest rate derivative instruments, net of tax	(8)	2	4
Other comprehensive income (loss)	(17)	(6)	(75)
Comprehensive income	$ 752	$ 431	$ 885