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Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses) (Details) (USD $) In Millions | 9 Months Ended |  |
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Sep. 30, 2011 Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses [Member] | Sep. 30, 2011 Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses [Member] Insurance Loss Recoverable [Member] | Sep. 30, 2011 Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses [Member] Recoveries On Unpaid Losses [Member] | Sep. 30, 2011 Non Variable Interest Entities [Member] | Dec. 31, 2010 Non Variable Interest Entities [Member]
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |  |  |
Gross Reserve as of beginning balance, Insurance Loss Recoverable |  | $ 2,531 |  | $ 2,770 | $ 2,531
Gross Reserve as of beginning balance, Recoveries on Unpaid Losses |  |  | 896 |  |
Gross Reserve as of beginning balance, Total | 3,427 |  |  |  |
Collections for Cases with Recoveries | (5) | (5) |  |  |
Accretion of Recoveries | 61 | 48 | 13 |  |
Changes in Discount Rates | 107 | 47 | 60 |  |
Changes in Timing of Collections |  |  |  |  |
Changes in Amount of Collections | (175) | (175) |  |  |
Changes in Assumptions | 18 | 315 | (297) |  |
Changes in LAE Recoveries | 24 | 9 | 15 |  |
Gross Reserve as of ending balance, Insurance Loss Recoverable |  | 2,770 |  | 2,770 | 2,531
Gross Reserve as of ending balance, Recoveries on Unpaid Losses |  |  | 687 |  |
Gross Reserve as of ending balance, Total | $ 3,457 |  |  |  |

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