| **Separate Account Balances and Changes (Details) - USD ($) $ in Millions**  | 3 Months Ended |
|------------------------------------------------------------------------------|----------------|
||
| **Separate Account, Liability [Roll Forward]**                               |           |   |
| Balance, beginning of period                                                 | $ 892          |   |
| Balance, end of period                                                       | 899            |   |
| Universal life                                                               |           |   |
| **Separate Account, Liability [Roll Forward]**                               |           |   |
| Balance, beginning of period                                                 | 892            | $ 959 |
| Interest credited before policy charges                                      | 10             | 10 |
| Change in unrealized gains and losses impacting separate account liabilities | 0              | (52) |
| Benefit payments                                                             | (2)            | (10) |
| Other                                                                        | (1)            | (4) |
| Balance, end of period                                                       | 899            | 903 |
| Cash surrender value                                                         | $ 896          | $ 869 |

| X                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Separated Account, Liability, Increase (Decrease) from Interest Credited before Policy Charges
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of cash outflow to separate account policyholder from benefit payment.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of separate account liability payable to policyholder upon surrender of contract before maturity.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase (decrease) in separate account liability from performance of investment.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount increase (decrease) in separate account liability from change, classified as other.
+ References
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| X                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of liability for variable contract in which all or portion of contract holder's funds is allocated to specific separate account and supported by assets held in separate account.
+ References
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| X                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------|
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