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Commitments, Contingencies, And Guarantees (Balance Sheet Locations, Fair Values In Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments) (Detail) - USD ($) $ in Millions | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Foreign currency forward contracts |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount |  | $ 3,711 | $ 4,134
Options/Futures contracts on notes and bonds |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount |  | 2,150 | 1,511
Convertible securities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount | [1] | 61 | 37
Investment And Embedded Derivative Instruments [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 95 | 112
Fair Value, Liability |  | (168) | (139)
Derivative, Notional Amount |  | 5,922 | 5,682
Futures contracts on equities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount | [2] | 1,119 | 939
Other Derivatives [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount |  | 368 | 0
Other Derivative Instruments [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount |  | 1,487 | 939
Designated as Hedging Instrument |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 48 | 17
Fair Value, Liability |  | (68) | 53
Derivative, Notional Amount |  | 3,203 | 3,199
Fair Value Hedging |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount |  | 1,609 | 1,595
Net Investment Hedging |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative, Notional Amount |  | 1,594 | 1,604
Other Assets [Member] | Foreign currency forward contracts |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 15 | 64
Other Assets [Member] | Options/Futures contracts on notes and bonds |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 27 | 18
Other Assets [Member] | Futures contracts on equities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset | [2] | 48 | 33
Other Assets [Member] | Other Derivatives [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 5 | 0
Other Assets [Member] | Other Derivative Instruments [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 53 | 33
Other Assets [Member] | Fair Value Hedging |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 48 | 17
Other Assets [Member] | Net Investment Hedging |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset |  | 0 | 0
Fixed Maturities [Member] | Convertible securities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative Asset, Fair Value, Gross Asset | [1] | 53 | 30
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign currency forward contracts |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability |  | (147) | (115)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options/Futures contracts on notes and bonds |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability |  | (21) | (24)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on equities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability | [2] | 0 | 0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivatives [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability |  | (4) | 0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability |  | (4) | 0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Fair Value Hedging |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability |  | 0 | 0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Net Investment Hedging |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability |  | (68) | (53)
Equity Securities | Convertible securities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair Value, Liability | [1] | $ 0 | $ 0
[1] | Includes fair value of embedded derivatives.
[2] | Related to MRB book of business.

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