| **Investments (Narrative) (Details) $ in Millions**                                    | 3 Months Ended | 9 Months Ended |        |
|----------------------------------------------------------------------------------------|----------------|----------------|--------|
||
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Mortgage loan losses due to changes in expected credit losses                          | $ 0            | $ 5            | $ 0    | $ 11 |   |
| Commitments to purchase or fund privately placed debt securities                       | 1,645          |           | 1,645  |   |   |
| Commitments to sell various privately placed debt securities                           | 90             |           | 90     |   |   |
| Fixed maturity securities                                                              | 42,579         |           | 42,579 |   | $ 40,425 |
| Net investment income                                                                  | 626            | 553            | 1,853  | 1,653 |   |
| Affiliated Entity                                                                      |           |           |   |   |   |
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Fixed maturity securities                                                              | 52             |           | 52     |   |   |
| Affiliated Entity | Maximum                                                            |           |           |   |   |   |
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Net investment income                                                                  | 1              |           |   |   |   |
| Mortgage loans                                                                         |           |           |   |   |   |
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Financing receivable, accrued interest, after allowance for credit loss                | 4              |           | 4      |   |   |
| Fixed maturity securities                                                              |           |           |   |   |   |
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Debt securities, available-for-sale, accrued interest, after allowance for credit loss | 451            | $ 430          | 451    | $ 430 | $ 435 |
| Commercial mortgage-backed                                                             |           |           |   |   |   |
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Amount of securitization                                                               | 305            |           | $ 305  |   |   |
| Commercial mortgage-backed | Affiliated Entity                                         |           |           |   |   |   |
| **Gain (Loss) on Securities [Line Items]**                                             |           |           |   |   |   |
| Related party transaction, amounts of transaction                                      | $ 50           |           |   |   |   |
| Number of tranches | tranche                                                           | 3              |           | 3      |   |   |

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Commitments To Sell Various Privately Placed Debt Securities
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Debt Securities, Number Of Investment Tranches
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The income earned from investments in securities and property, equipment and other capital assets. It includes rent from property and equipment, dividends from shares in corporations, and interest from bonds, loans, mortgages, derivatives, commercial paper, bank accounts, certificates of deposits, treasuries, and other financial securities. It also includes realized gains and losses on trading securities.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).
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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, after allowance for credit loss, of accrued interest on financing receivable.
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Amount of credit loss expense (reversal of expense) for financing receivable.
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Amount of transactions with related party during the financial reporting period.
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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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