XML 1124 R97.htm IDEA: XBRL DOCUMENT

Summary of Changes in Valuation Allowance (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 432	$ 479	$ 579
Changes in Related Gross Deferred Tax Assets/Liabilities	11	(40)	(45)
Charge/Release	(302)	(7)	(55)
Balance at End of Period	$ 141	$ 432	$ 479

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

The amount of the change in the period in the valuation allowance for a specified deferred tax asset.