Summarized Financial Information for Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	$ 10	$ 12
Income from operations before income taxes	3
Income tax provision	(1)
Loss on sale, net of income taxes	(2)
Income (loss) from discontinued operations

Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component.

+ References+ Details

Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

+ References

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+ Details