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Tax - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reconciliation Of Statutory Federal Tax Rate [Line Items]
Effective tax rate	28.80%	30.60%	30.30%	30.70%
U.S. federal statutory rate			35.00%
Unrecognized tax benefit	$ 128		$ 128
Increase in unrecognized tax benefit			1
Realized [Member]
Reconciliation Of Statutory Federal Tax Rate [Line Items]
Unrecognized tax benefit	$ 55		$ 55

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

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

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-Glossary Unrecognized Tax Benefit

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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