| **Investments (Narrative) (Details) - USD ($)**                                                                   | 12 Months Ended |                 |        |
|-------------------------------------------------------------------------------------------------------------------|-----------------|-----------------|--------|
||
| **Gain (Loss) on Investments [Line Items]**                                                                       |            |            |   |
| Non-income producing fixed maturity securities                                                                    | $ 2,000,000     | $ 0             |   |
| Investments that exceed ten percent of stockholders' equity                                                       | 0               | 0               |   |
| Repayments of senior debt                                                                                         | 350,000,000     |            |   |
| Limited partnership investments                                                                                   | 2,369,000,000   | 2,371,000,000   |   |
| Undistributed earnings of limited partnership investments                                                         | $ 539,000,000   | $ 523,000,000   |   |
| Percentage of limited partnerships reported on a current basis                                                    | 61.00%          |            |   |
| Percentage of limited partnerships reported on a one month lag                                                    | 18.00%          |            |   |
| Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments | 71.00%          | 68.00%          |   |
| Limited partnerships invested in private debt and equity                                                          | 25.00%          | 27.00%          |   |
| Percentage of equity related limited partnership hedge fund strategies                                            | 62.00%          |            |   |
| Percentage of multistrategy approach limited partnership hedge fund strategies                                    | 19.00%          |            |   |
| Percentage of distressed investments limited partnership hedge fund strategies                                    | 17.00%          |            |   |
| Percentage of fixed income limited partnership hedge fund strategies                                              | 2.00%           |            |   |
| Carrying value of ten largest limited partnerships                                                                | $ 1,136,000,000 | $ 1,168,000,000 |   |
| Carrying value of limited partnerships as percentage of aggregate partnership equity                              | 3.00%           | 4.00%           |   |
| Income As Percentage Of Change In Partnership Equity For All Limited Partnerships                                 | 3.00%           | 4.00%           | 3.00%  |
| RIght to reclaim cash                                                                                             | $ 0             | $ 0             |   |
| Obligation to return cash                                                                                         | 0               | 0               |   |
| Derivative, notional amount                                                                                       | 167,000,000     | 174,000,000     |   |
| Derivative liability, fair value, gross liability                                                                 | 3,000,000       | (3,000,000)     |   |
| Future capital call commitments for limited partnership investments                                               | 384,000,000     |            |   |
| Mortgage loan commitments                                                                                         | 46,000,000      |            |   |
| Commitments to purchase or fund privately placed debt securities                                                  | 165,000,000     |            |   |
| Commitments to sell various privately placed debt securities                                                      | 108,000,000     |            |   |
| Carrying value of securities deposited under requirements of regulatory authorities                               | 2,600,000,000   | 2,300,000,000   |   |
| Cash and securities deposited as collateral for letters of credit                                                 | 471,000,000     | 514,000,000     |   |
| Carrying value of assets deposited to secure reinsurance and third party obligations                              | 587,000,000     | 261,000,000     |   |
| Non-income producing fixed maturity securities                                                                    | 2,000,000       | 0               |   |
| Investments that exceed ten percent of stockholders' equity                                                       | 0               | 0               |   |
| Repayments of senior debt                                                                                         | 350,000,000     |            |   |
| Limited partnership investments                                                                                   | 2,369,000,000   | 2,371,000,000   |   |
| Undistributed earnings of limited partnership investments                                                         | $ 539,000,000   | $ 523,000,000   |   |
| Percentage of limited partnerships reported on a current basis                                                    | 61.00%          |            |   |
| Percentage of limited partnerships reported on a one month lag                                                    | 18.00%          |            |   |
| Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments | 71.00%          | 68.00%          |   |
| Limited partnerships invested in private debt and equity                                                          | 25.00%          | 27.00%          |   |
| Percentage of equity related limited partnership hedge fund strategies                                            | 62.00%          |            |   |
| Percentage of multistrategy approach limited partnership hedge fund strategies                                    | 19.00%          |            |   |
| Percentage of distressed investments limited partnership hedge fund strategies                                    | 17.00%          |            |   |
| Percentage of fixed income limited partnership hedge fund strategies                                              | 2.00%           |            |   |
| Carrying value of ten largest limited partnerships                                                                | $ 1,136,000,000 | $ 1,168,000,000 |   |
| Carrying value of limited partnerships as percentage of aggregate partnership equity                              | 3.00%           | 4.00%           |   |
| Income As Percentage Of Change In Partnership Equity For All Limited Partnerships                                 | 3.00%           | 4.00%           | 3.00%  |
| RIght to reclaim cash                                                                                             | $ 0             | $ 0             |   |
| Obligation to return cash                                                                                         | 0               | 0               |   |
| Derivative, notional amount                                                                                       | 167,000,000     | 174,000,000     |   |
| Derivative liability, fair value, gross liability                                                                 | (3,000,000)     | 3,000,000       |   |
| Future capital call commitments for limited partnership investments                                               | 384,000,000     |            |   |
| Mortgage loan commitments                                                                                         | 46,000,000      |            |   |
| Commitments to purchase or fund privately placed debt securities                                                  | 165,000,000     |            |   |
| Commitments to sell various privately placed debt securities                                                      | 108,000,000     |            |   |
| Carrying value of securities deposited under requirements of regulatory authorities                               | 2,600,000,000   | 2,300,000,000   |   |
| Cash and securities deposited as collateral for letters of credit                                                 | 471,000,000     | 514,000,000     |   |
| Carrying value of assets deposited to secure reinsurance and third party obligations                              | 587,000,000     | $ 261,000,000   |   |
| Senior Notes, Due November 2019                                                                                   |            |            |   |
| **Gain (Loss) on Investments [Line Items]**                                                                       |            |            |   |
| Realized investment gains (losses)                                                                                | 42,000,000      |            |   |
| Realized investment gains (losses)                                                                                | $ 42,000,000    |            |   |

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Carrying Value of Assets Deposited to Secure Reinsurance and Third Party Obligations
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Carrying value Of Limited Partnerships As Percentage of Aggregate Partnership Equity
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Carrying Value Of Securities Deposited Under Requirements Of Regulatory Authorities
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Carrying Value Of Ten Largest Limited Partnerships
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Cash And Securities Deposited As Collateral For Letters Of Credit
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Commitments To Purchase Or Fund Additional Amounts
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Commitments To Sell Various Privately Placed Debt Securities
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Future capital call commitments to limited partnerships for which we would receive an ownership interest.
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Income As Percentage Of Change In Partnership Equity For All Limited Partnerships
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Investments that Exceed Ten Percent of Stockholders' Equity, other than investments in U.S. Treasury and U.S. Government agency securities.
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This item represents the carrying amount on the entity's balance sheet of its investment in limited partnerships.
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Limited Partnerships Invested In Private Debt and Equity
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Mortgage loan commitments, representing signed loan applications received and accepted.
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Non-Income Producing Fixed Maturity Securities
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Percentage of Distressed Investments Limited Partnership Hedge Fund Strategies
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Percentage of Equity Related Limited Partnership Hedge Fund Strategies
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Percentage of Fixed Income Limited Partnership Hedge Fund Strategies
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Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments
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Percentage of total carrying value of limited partnerships reported on a current basis
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Percentage of total carrying value of limited partnerships reported on a one month lag.
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Percentage of Multistrategy Approach Limited Partnership Hedge Fund Strategies
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| - Definition
Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.
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| - Definition
Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.
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| - Definition
Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.
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| - Definition
The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.
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| - Definition
The cash outflow for a long-term debt where the holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period.
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| - Definition
Amount of consolidated retained earnings that represent undistributed (not yet received) earnings from 50% or less owned persons accounted for by the equity method (equity method investees).
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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