| **Separate Account Balances and Changes (Details) - USD ($) $ in Millions**   | 3 Months Ended | 9 Months Ended |
|-------------------------------------------------------------------------------|----------------|----------------|
||
| **Separate Account, Liability [Roll Forward]**                                |           |           |   |   |
| Balance, beginning of period                                                  |           |           | $ 892 |   |
| Balance, end of period                                                        | $ 918          |           | 918 |   |
| Universal life                                                                |           |           |   |   |
| **Separate Account, Liability [Roll Forward]**                                |           |           |   |   |
| Balance, beginning of period                                                  | 911            | $ 860          | 892 | $ 959 |
| Interest credited before policy charges                                       | 11             | 9              | 31 | 29 |
| Change in unrealized gains and losses impacting separate accounts liabilities | 0              | 20             | 0 | (85) |
| Benefit payments                                                              | (3)            | 0              | (6) | (10) |
| Other                                                                         | (1)            | (1)            | 1 | (5) |
| Balance, end of period                                                        | 918            | 888            | 918 | 888 |
| Cash surrender value                                                          | $ 912          | $ 886          | $ 912 | $ 886 |

| 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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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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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