Financial Instruments - Derivative Foreign Currency Contracts at Gross Fair Value and Unrecognized Impacts of Master Netting Arrangements (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Offsetting [Abstract]
Assets, Gross amounts presented in consolidated balance sheets	$ 30	$ 62
Assets, Gross amounts not offset in consolidated balance sheets	28	42
Assets, Net amounts	2us-gaap_DerivativeAssets	20us-gaap_DerivativeAssets
Liabilities, Gross amounts presented in Consolidated Balance Sheets	(174)	(65)
Liabilities, Gross amounts not offset in Consolidated Balance Sheets	(28)	(42)
Liabilities, Net Amounts	$ (146)us-gaap_DerivativeLiabilities	$ (23)us-gaap_DerivativeLiabilities

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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- Definition

Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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