Schedule of Derivative Instruments not Designated as Hedges Gains (Losses) (Detail) (Not Designated as Hedging Instrument, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Nonoperating income (expense): Miscellaneous, net	$ (462)	$ 79	$ 38