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Investments Investments - Equity Investments (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2024 | Mar. 31, 2023 | Dec. 31, 2023
Schedule of Equity Method Investments [Line Items] |  |  |
Equity Securities Excluded From Fair Value Table | $ 13 |  | $ 13
Equity Securities, FV-NI, Realized Gain (Loss) | 0 | $ 2 |
Debt Securities, Available-for-sale, Allowance for Credit Loss | 2 | 1 | 3
Net Realized and Unrealized Gain (Loss) on Trading Securities |  | $ 7 |
Debt Securities, Trading, Realized Gain (Loss) | 7 |  |
Real Estate [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments |  |  | 21
Hedge Funds, Multi-strategy [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 115 |  | 112
Illiquid Investments [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 85 |  | 84
Insurance Linked [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 0 |  | 1
Private Equity Funds [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 75 |  | 70
Equity investments in pooled funds [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 546 |  | 463
Equity Securities Excluded From Fair Value |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 |  | 0
Convertibles and Bonds with Warrants Attached |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 16 |  | 0
Fixed Income Funds |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 52 |  | 52
Equity Funds |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 40 |  | 38
Real Estate Funds |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 20 |  |
High Yield Fund |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 142 |  | 85
Priced Through Pricing Vendors [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 152 |  | 77
Priced Through Pricing Vendors [Member] | Interest Rate Contract [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 95 |  | 39
Priced Through Pricing Vendors [Member] | Equity [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 40 |  | 38
Priced Through Pricing Vendors [Member] | Convertibles and Bonds with Warrants Attached |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | 16 |  | $ 0
Commitments [Member] | Private Equity Funds [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Other investments | $ 35 |  |

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