Components of Special Charges (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating:
Labor agreement costs	$ 100
Cleveland airport lease restructuring	74
Severance and benefit costs	8	$ 50
(Gains) losses on sale of assets and other special charges	8	14
Special charges	190	64
Nonoperating and income taxes:
Loss on extinguishment of debt and other	8	6
Income tax benefit related to special charges	(72)
Total special charges, net of tax	$ 126	$ 70