Components of Special Items (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating:
Labor agreement costs	$ 14		$ 124
Severance and benefit costs	13	$ 28	27	$ 103
Cleveland airport lease restructuring			74
(Gains) losses on sale of assets and other special charges	18	48	32	92
Special charges	45	76	669	195
Nonoperating and income taxes:
Losses on extinguishment of debt and other		61	(1)	195
Income tax benefit related to special charges	(16)		(241)
Total special charges, net of tax	29	137	427	390
Income tax valuation allowance release (Note 4)		(3,218)		(3,218)
Total special items	$ 29	$ (3,081)	427	$ (2,828)
Newark Liberty International Airport
Operating:
Impairment of intangible asset related to Newark Liberty International Airport ("Newark") slots			$ 412

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Period expense related to postemployment benefits.

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