Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Net deferred tax asset	$ 1,000,000,000	$ 1,000,000,000	$ 1,300,000,000
Valuation allowance	59,000,000	59,000,000	32,000,000
Valuation allowance increased during the period	27,000,000	27,000,000
Unrecognized tax benefits (UTBs)	56,000,000	56,000,000	39,000,000
UTBs that would reduce the effective tax rate, if recognized	$ 40,000,000	$ 40,000,000	$ 25,000,000

For entities that net deferred tax assets and tax liabilities, represents the unclassified net amount of deferred tax assets and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities. A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods.

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The amount of the valuation allowance recorded as of the balance sheet date pertaining to the specified deferred tax asset for which an assessment was made that it is more likely than not that all or a portion of such deferred tax asset will not be realized through related deductions on future tax returns.

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