Other Income, Net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other Non operating Income Expense [Line Items]
Net loss (gain) from asset sales	$ 30	$ 28	$ 28	$ 28
Disposal of Equity Interests [Member]
Other Non operating Income Expense [Line Items]
Net loss (gain) from asset sales	$ 27		$ 27
Disposal of Land [Member]
Other Non operating Income Expense [Line Items]
Net loss (gain) from asset sales		$ 29		$ 29