| **Claim and Claim Adjustment Expense Reserves (Reconcilliation of claim and claim adjustment expense reserves) (Details) (USD $)In Millions, unless otherwise specified**                                                                                                                                                                                              | 12 Months Ended |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Reserves, beginning of year:**                                                                                                                                                                                                                                                                                                                                       |            |  |   |  |   |  |
| Gross                                                                                                                                                                                                                                                                                                                                                                  | $ 25,496        |  | $ 26,816 |  | $ 27,593 |  |
| Ceded                                                                                                                                                                                                                                                                                                                                                                  | 6,122           |  | 5,594 |  | 6,288 |  |
| Net reserves, beginning of year                                                                                                                                                                                                                                                                                                                                        | 19,374          |  | 21,222 |  | 21,305 |  |
| Reduction of net reserves due to the Loss Portfolio Transfer transaction                                                                                                                                                                                                                                                                                               |       |  | (1,381) |  |    |  |
| Reduction of net reserves due to disposition of subsidiaries                                                                                                                                                                                                                                                                                                           | (277)           |  | (98) |  |    |  |
| **Net incurred claim and claim adjustment expenses:**                                                                                                                                                                                                                                                                                                                  |            |  |   |  |   |  |
| Provision for insured events of current year                                                                                                                                                                                                                                                                                                                           | 4,904           |  | 4,741 |  | 4,793 |  |
| Increase (decrease) in provision for insured events of prior years                                                                                                                                                                                                                                                                                                     | (429)           |  | (544) |  | (240) |  |
| Amortization of discount                                                                                                                                                                                                                                                                                                                                               | 135             |  | 123 |  | 122 |  |
| Total net incurred (a)                                                                                                                                                                                                                                                                                                                                                 | 4,610           | [1] | 4,320 | [1] | 4,675 | [1] |
| **Net payments attributable to:**                                                                                                                                                                                                                                                                                                                                      |            |  |   |  |   |  |
| Current year events                                                                                                                                                                                                                                                                                                                                                    | (1,029)         |  | (908) |  | (917) |  |
| Prior year events                                                                                                                                                                                                                                                                                                                                                      | (3,473)         |  | (3,776) |  | (3,939) |  |
| Total net payments                                                                                                                                                                                                                                                                                                                                                     | (4,502)         |  | (4,684) |  | (4,856) |  |
| Foreign currency translation adjustment and other                                                                                                                                                                                                                                                                                                                      | 78              |  | (5) |  | 98 |  |
| Net reserves, end of year                                                                                                                                                                                                                                                                                                                                              | 19,283          |  | 19,374 |  | 21,222 |  |
| Ceded reserves, end of year                                                                                                                                                                                                                                                                                                                                            | 5,020           |  | 6,122 |  | 5,594 |  |
| Gross reserves, end of year                                                                                                                                                                                                                                                                                                                                            | $ 24,303        |  | $ 25,496 |  | $ 26,816 |  |
|                                                                                                                                                                                                                                                                                                                                                                        |
| [1]Total net incurred above does not agree to Insurance claims and policyholders' benefits as reflected on the Consolidated Statements of Operations due to amounts related to uncollectible reinsurance and loss deductible receivables, and benefit expenses related to future policy benefits and policyholders' funds, which are not reflected in the table above. |

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Liability for Unpaid Claims and Claims Adjustment Expense Incurred Claims Amortization of Discount
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| - Definition
Total amount of payments made during the reporting period to settle insured claims and pay costs incurred in the claims settlement process.
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| - Definition
Amount of payments made in the reporting period to settle claims incurred in the current period and related claims settlement costs.
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| - Definition
Amount of payments made in the reporting period to settle claims incurred in prior periods and related claims settlement costs.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The estimated cost of settling claims under the terms of the underlying insurance policies and assumed and ceded insurance contracts as of the balance sheet date, including an estimate for claims which have been incurred but not reported and the actual and estimated costs of settling claims.
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Total provision in the period for claims incurred and costs incurred in the claim settlement process.
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| - Definition
Amount of provision in the period for claims incurred in the reporting period and related claims settlement costs.
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| - Definition
Amount of provision in the period for claims incurred in prior reporting periods and related claims settlement costs.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims.
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