Tax - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Tax Credit Carryforward [Line Items]
Effective tax rate	18.80%	28.80%	30.40%	30.30%
Effective tax rate excluding discrete items	20.30%		27.80%
U.S. federal statutory rate			35.00%
Unrecognized tax benefit	$ 113		$ 113
Total uncertain tax position identified in foreign jurisdiction			69
Uncertain tax position settled			69
Realized [Member]
Tax Credit Carryforward [Line Items]
Unrecognized tax benefit	$ 40		$ 40

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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-SubTopic 10

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from settlements with taxing authorities.

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