Components of Special Charges (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating:
Severance and benefit costs	$ 14	$ 37
Impairment of assets	23
(Gains) losses on sale of assets and other special charges	3	14
Special charges	40	51	[1]
Income tax benefit related to special charges	(9)	(18)
Total special charges, net of tax	$ 31	$ 33

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) and Accounting Standards Update No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. See Note 1 to the financial statements contained in Part I, Item 1 of this report for additional information.