Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ (4,206)	$ (2,554)
Other comprehensive income (loss) before reclassifications	(283)	(61)
Amounts reclassified from accumulated other comprehensive loss	219	70
Income taxes	(15)	(10)
Net other comprehensive income (loss)	(79)	(1)
Ending Balance	(4,285)	(2,555)
Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,531)	(1,068)
Other comprehensive income (loss) before reclassifications	(113)	(88)
Net other comprehensive income (loss)	(113)	(88)
Ending Balance	(1,644)	(1,156)
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(96)	29
Other comprehensive income (loss) before reclassifications	(152)	16
Amounts reclassified from accumulated other comprehensive loss	118	(3)
Net other comprehensive income (loss)	(34)	13
Ending Balance	(130)	42
Pension and Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(2,589)	(1,691)
Amounts reclassified from accumulated other comprehensive loss	101	73
Income taxes	(15)	(10)
Net other comprehensive income (loss)	86	63
Ending Balance	(2,503)	(1,628)
Unrealized Gain/(Loss) on Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	10	176
Other comprehensive income (loss) before reclassifications	(18)	11
Net other comprehensive income (loss)	(18)	11
Ending Balance	$ (8)	$ 187