Summary of Significant Accounting Policies (Details) (General Insurance Group [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2012
General Insurance Group [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs	$ 9	$ 31

Amount of deferred policy acquisition costs charged to expense in the period, generally in proportion to related revenue earned, estimated gross profits, or over the customer relationship or some other period.

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 6: http://www.xbrl.org/2003/role/presentationRef

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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