| **Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details) $ in Millions** | Jun. 30, 2023 USD ($) | Dec. 31, 2022 USD ($) |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------|-----------------------|
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Estimated fair value                                                                                                                                    | $ 41,164              | $ 39,980              |
| Fixed maturity securities | Discounted cash flow                                                                                                        |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Estimated fair value                                                                                                                                    | $ 1,415               | $ 1,177               |
| Credit spread | Discounted cash flow | Minimum                                                                                                          |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Debt securities, available-for-sale, measurement Input                                                                                                  | 0.01                  | 0.01                  |
| Credit spread | Discounted cash flow | Maximum                                                                                                          |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Debt securities, available-for-sale, measurement Input                                                                                                  | 0.07                  | 0.08                  |
| Credit spread | Discounted cash flow | Weighted Average                                                                                                 |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Debt securities, available-for-sale, measurement Input                                                                                                  | 0.02                  | 0.02                  |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.
+ References
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2
+ Details**Name:**us-gaap_AssetsFairValueDisclosure**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
+ References
Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2
+ Details**Name:**us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput**Namespace Prefix:**us-gaap_**Data Type:**xbrli:decimalItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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.
+ References
No definition available.
+ Details**Name:**us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByAssetClassAxis=us-gaap_FixedIncomeSecuritiesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueDiscountedCashFlowMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputCreditSpreadMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_RangeAxis=srt_MinimumMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_RangeAxis=srt_MaximumMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_RangeAxis=srt_WeightedAverageMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |