CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE OPERATIONS (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Income	$ 104	$ 68	$ 141	$ 109
Related to marketable securities:
Unrealized holding gains (losses) arising during the period	(11)	1	(12)	4
Reclassification adjustment for gains included in net income	(1)	(2)	(2)	(2)
Income tax effect	4	0	5	(1)
Marketable securities, net of tax	(8)	(1)	(9)	1
Related to employee benefit plans:
Prior service cost arising during period	11	10	21	20
Income tax effect	(3)	(4)	(7)	(8)
Employee benefit plans, net of tax	8	6	14	12
Related to interest rate derivative instruments:
Unrealized holding gains arising during the period	7	(8)	10	(6)
Reclassification of (gain) loss into net income (within Aircraft rent)	2	1	3	3
Income tax effect	(4)	3	(6)	(1)
Interest rate derivative instruments, net of tax	5	(4)	7	(4)
Other comprehensive income	5	1	12	9
Comprehensive income	$ 109	$ 69	$ 153	$ 118