Reinsurance Additional Information (Detail) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2010	Mar. 31, 2010	Jun. 30, 2010
Reduction in ceded reserves and incurred loss and loss expenses	$ 33		$ 44
Reduction in ceded reserves, increased net incurred loss and loss expenses	21
Reduction in direct reserves	33
Reduction of ceded IBNR reserves		$ 7

Increase Decrease In Ceded Incurred But Not Reported (IBNR) Reserve

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- Definition

The net change during the reporting period for the aggregate amount of policy reserves (provided for future obligations including unpaid claims and claims adjustment expenses) and policy benefits (liability for future policy benefits) as of the balance sheet date; grouped amount of all the liabilities associated with the company's insurance policies.

+ Details

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- Definition

The reduction in the amount of the provision for the period for claims and benefits incurred on contract risks ceded to other insurers under reinsurance arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 113
-Paragraph 27, 113
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387

+ Details

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- Definition

The amount of the provision for the period for claims and benefits incurred on contracts acquired by the insurer during the period in other than reinsurance arrangements.

+ References

+ Details

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