Stockholders' Equity - Schedule of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ (4,206)	$ (2,554)	$ (3,888)
Other comprehensive income (loss) before reclassifications	(960)	(2,152)	1,261
Amounts reclassified from accumulated other comprehensive loss	682	418	375
Income taxes	(74)	82	(302)
Ending Balance	(4,558)	(4,206)	(2,554)
Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,531)	(1,068)	(917)
Other comprehensive income (loss) before reclassifications	(522)	(463)	(151)
Ending Balance	(2,053)	(1,531)	(1,068)
Unrealized Gain/(Loss) on Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	10	176	141
Other comprehensive income (loss) before reclassifications	(50)	(166)	35
Amounts reclassified from accumulated other comprehensive loss	40
Ending Balance		10	176
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(96)	29	30
Other comprehensive income (loss) before reclassifications	(178)	(238)	49
Amounts reclassified from accumulated other comprehensive loss	235	113	(50)
Ending Balance	(39)	(96)	29
Pension and Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(2,589)	(1,691)	(3,142)
Other comprehensive income (loss) before reclassifications	(210)	(1,285)	1,328
Amounts reclassified from accumulated other comprehensive loss	407	305	425
Income taxes	(74)	82	(302)
Ending Balance	$ (2,466)	$ (2,589)	$ (1,691)