| **Investments (Narrative) (Details) - USD ($)**                                                                                                                                                                                                                                                                                                                                                                                                                                        | 12 Months Ended |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Gain (Loss) on Securities [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                             |            |   |  |   |
| Non-income producing fixed maturity securities                                                                                                                                                                                                                                                                                                                                                                                                                                         | $ 0             | $ 0 |  |   |
| Non-income producing mortgage loans                                                                                                                                                                                                                                                                                                                                                                                                                                                    | 20,000,000      | 7,000,000 |  |   |
| Investments that exceed ten percent of stockholders' equity                                                                                                                                                                                                                                                                                                                                                                                                                            | 0               | 0 |  |   |
| Investment and derivative, realized gain (loss), coinsurance agreement                                                                                                                                                                                                                                                                                                                                                                                                                 |            | 18,000,000 |  |   |
| Gross gains                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | 75,000,000      | 120,000,000 |  | $ 186,000,000 |
| Debt securities, available-for-sale, realized loss                                                                                                                                                                                                                                                                                                                                                                                                                                     | 166,000,000     | 261,000,000 |  | 90,000,000 |
| Mortgage loan losses due to changes in expected credit losses                                                                                                                                                                                                                                                                                                                                                                                                                          | 11,000,000      | 8,000,000 |  | $ (10,000,000) |
| Limited partnership investments                                                                                                                                                                                                                                                                                                                                                                                                                                                        | 2,174,000,000   | 1,926,000,000 | [1] |   |
| Undistributed earnings of limited partnership investments                                                                                                                                                                                                                                                                                                                                                                                                                              | $ 250,000,000   | $ 176,000,000 |  |   |
| Percentage of limited partnerships reported on a current basis                                                                                                                                                                                                                                                                                                                                                                                                                         | 17.00%          |   |  |   |
| Percentage of limited partnerships reported on a one month lag                                                                                                                                                                                                                                                                                                                                                                                                                         | 4.00%           |   |  |   |
| Limited partnerships invested in private debt and equity                                                                                                                                                                                                                                                                                                                                                                                                                               | 85.00%          | 76.00% |  |   |
| Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments                                                                                                                                                                                                                                                                                                                                                                      | 15.00%          | 24.00% |  |   |
| Carrying value of ten largest limited partnerships                                                                                                                                                                                                                                                                                                                                                                                                                                     | $ 622,000,000   | $ 633,000,000 |  |   |
| Carrying value of limited partnerships as percentage of aggregate partnership equity                                                                                                                                                                                                                                                                                                                                                                                                   | 1.00%           | 1.00% |  |   |
| Income as percentage of change in partnership equity for all limited partnerships                                                                                                                                                                                                                                                                                                                                                                                                      | 1.00%           | 2.00% |  | 2.00% |
| Obligation to return cash                                                                                                                                                                                                                                                                                                                                                                                                                                                              | $ 1,000,000     |   |  |   |
| Derivative liability, subject to master netting arrangement, collateral, right to reclaim cash offset                                                                                                                                                                                                                                                                                                                                                                                  | 0               | $ 0 |  |   |
| Increase (decrease) fixed maturity securities                                                                                                                                                                                                                                                                                                                                                                                                                                          | 224,000,000     |   |  |   |
| Increase (decrease) short term investments                                                                                                                                                                                                                                                                                                                                                                                                                                             | 4,000,000       |   |  |   |
| Increase (decrease) accrued investment income                                                                                                                                                                                                                                                                                                                                                                                                                                          | 2,000,000       |   |  |   |
| Increase (decrease) funds withheld liability                                                                                                                                                                                                                                                                                                                                                                                                                                           | 216,000,000     |   |  |   |
| Embedded derivative, fair value of embedded derivative liability                                                                                                                                                                                                                                                                                                                                                                                                                       | 14,000,000      |   |  |   |
| Commitments to purchase or fund privately placed debt securities                                                                                                                                                                                                                                                                                                                                                                                                                       | 1,555,000,000   |   |  |   |
| Commitments to sell various privately placed debt securities                                                                                                                                                                                                                                                                                                                                                                                                                           | 35,000,000      |   |  |   |
| Carrying value of securities deposited under requirements of regulatory authorities                                                                                                                                                                                                                                                                                                                                                                                                    | 3,100,000,000   | 2,800,000,000 |  |   |
| Cash and securities deposited as collateral for letters of credit                                                                                                                                                                                                                                                                                                                                                                                                                      | 900,000,000     |   |  |   |
| Fixed maturity securities                                                                                                                                                                                                                                                                                                                                                                                                                                                              |            |   |  |   |
| **Gain (Loss) on Securities [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                             |            |   |  |   |
| OCI, debt securities, available-for-sale, gain (loss), after adjustment, before tax                                                                                                                                                                                                                                                                                                                                                                                                    | 1,431,000,000   | (7,850,000,000) |  | $ (1,272,000,000) |
| Debt securities, available-for-sale, accrued interest, after allowance for credit loss                                                                                                                                                                                                                                                                                                                                                                                                 | 435,000,000     | 394,000,000 |  |   |
| Mortgage loans                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |            |   |  |   |
| **Gain (Loss) on Securities [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                             |            |   |  |   |
| Financing receivable, accrued interest, after allowance for credit loss                                                                                                                                                                                                                                                                                                                                                                                                                | $ 4,000,000     |   |  |   |
| Funds Withheld Liability Securities                                                                                                                                                                                                                                                                                                                                                                                                                                                    |            |   |  |   |
| **Gain (Loss) on Securities [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                             |            |   |  |   |
| Gross gains                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |            | 62,000,000 |  |   |
| Debt securities, available-for-sale, realized loss                                                                                                                                                                                                                                                                                                                                                                                                                                     |            | $ 44,000,000 |  |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| [1]As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021.  Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance.  See Note A to the Consolidated Financial Statements for additional information. |

| X                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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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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Income As Percentage Of Change In Partnership Equity For All Limited Partnerships
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Increase (Decrease) Accrued Investment Income
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Increase (Decrease) Fixed Maturity Securities
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Increase (Decrease) Funds Withheld Liability
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Increase (Decrease) Short Term Investments
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Investment and Derivative, Realized Gain (Loss), Coinsurance Agreement
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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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Non-Income Producing Fixed Maturity Securities
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Non-Income Producing Mortgage Loans
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| - Definition
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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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
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| - Definition
Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
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| - Definition
Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
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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 offset against derivative liabilities.
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| - Definition
Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.
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| - Definition
Amount, after allowance for credit loss, of accrued interest on financing receivable.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount, before tax and after adjustment, of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.
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| - Definition
Amount of credit loss expense (reversal of expense) for financing receivable.
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| - Definition
Amount of consolidated retained earnings that represent undistributed (not yet received) earnings from 50 percent 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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