Income Taxes - Components of Income Tax Table (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current [Abstract]
Federal	$ 188us-gaap_CurrentFederalTaxExpenseBenefit	$ 113us-gaap_CurrentFederalTaxExpenseBenefit	$ 45us-gaap_CurrentFederalTaxExpenseBenefit
State	2	42	25
Foreign	1,574us-gaap_CurrentForeignTaxExpenseBenefit	873us-gaap_CurrentForeignTaxExpenseBenefit	891us-gaap_CurrentForeignTaxExpenseBenefit
Total	1,764us-gaap_CurrentIncomeTaxExpenseBenefit	1,028us-gaap_CurrentIncomeTaxExpenseBenefit	961us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred [Abstract]
Federal	(389)	94	(30)
State	27	(9)	115
Foreign	215	52	74
Total	(147)us-gaap_DeferredIncomeTaxExpenseBenefit	137us-gaap_DeferredIncomeTaxExpenseBenefit	159us-gaap_DeferredIncomeTaxExpenseBenefit
Total income tax expense (benefit)	$ 1,617us-gaap_IncomeTaxExpenseBenefit	$ 1,165us-gaap_IncomeTaxExpenseBenefit	$ 1,120us-gaap_IncomeTaxExpenseBenefit

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