Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ (4,206)	$ (2,554)
Other comprehensive (loss) income before reclassifications	(214)	13
Amounts reclassified from accumulated other comprehensive loss	334	162
Income taxes	(22)	(20)
Net other comprehensive income (loss)	98	155
Ending Balance	(4,108)	(2,399)
Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,531)	(1,068)
Other comprehensive (loss) income before reclassifications	(94)	(30)
Net other comprehensive income (loss)	(94)	(30)
Ending Balance	(1,625)	(1,098)
Unrealized Gain/(Loss) on Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	10	176
Other comprehensive (loss) income before reclassifications	(10)	30
Net other comprehensive income (loss)	(10)	30
Ending Balance		206
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(96)	29
Other comprehensive (loss) income before reclassifications	(110)	13
Amounts reclassified from accumulated other comprehensive loss	140	6
Net other comprehensive income (loss)	30	19
Ending Balance	(66)	48
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	194	156
Income taxes	(22)	(20)
Net other comprehensive income (loss)	172	136
Ending Balance	$ (2,417)	$ (1,555)