Amount of OTTI Charges (Detail) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other-than-temporary impairments on fixed maturity securities	$ 3	$ 1	$ 3	$ 3
Other-than-temporary impairments on equity securities			30	33
Other-than-temporary impairment charges	$ 3	$ 1	$ 33	$ 36

- Definition

The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

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