Other Income, Net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Non operating Income Expense [Line Items]
Net loss (gain) from asset sales	$ 124	$ 41	$ 152	$ 69
Disposal of Equity Interests [Member]
Other Non operating Income Expense [Line Items]
Net loss (gain) from asset sales			27
Disposal of Land [Member]
Other Non operating Income Expense [Line Items]
Net loss (gain) from asset sales	$ 118		$ 118	$ 29