Stockholders' Equity - Schedule of Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ (2,554)	$ (3,888)	$ (3,557)
Other comprehensive income (loss) before reclassifications	(2,152)	1,261	(707)
Amounts reclassified from accumulated other comprehensive loss	418	375	276
Income taxes	82	(302)	100
Balance	(4,206)	(2,554)	(3,888)
Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(1,068)	(917)	(993)
Other comprehensive income (loss) before reclassifications	(463)	(151)	76
Balance	(1,531)	(1,068)	(917)
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	29	30	(26)
Other comprehensive income (loss) before reclassifications	(238)	49	92
Amounts reclassified from accumulated other comprehensive loss	113	(50)	(36)
Balance	(96)	29	30
Pension and Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(1,691)	(3,142)	(2,538)
Other comprehensive income (loss) before reclassifications	(1,285)	1,328	(1,016)
Amounts reclassified from accumulated other comprehensive loss	305	425	312
Income taxes	82	(302)	100
Balance	(2,589)	(1,691)	(3,142)
Unrealized Gain on Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	176	141
Other comprehensive income (loss) before reclassifications	(166)	35	141
Balance	$ 10	$ 176	$ 141