Other Expenses (Income), Net - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2012
Suriname Mining Interest [Member]
Component of Other Income, Nonoperating [Abstract]
Net gain from asset sales	$ 28
China Rolling Mill Equity Investment [Member]
Component of Other Income, Nonoperating [Abstract]
Net gain from asset sales	14
Tapoco Hydroelectric Project [Member]
Component of Other Income, Nonoperating [Abstract]
Net gain from asset sales		$ 320