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		Mar. 31, 2023	Dec. 31, 2022
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		$ 4,387	$ 4,134
Options/Futures contracts on notes and bonds
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,861	1,511
Convertible securities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[1]	37	37
Investment And Embedded Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		89	112
Fair Value, Liability		(158)	(139)
Derivative, Notional Amount		6,285	5,682
Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[2]	925	939
Other Derivatives [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		457	0
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,382	939
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		8	17
Fair Value, Liability		(82)	53
Derivative, Notional Amount		3,166	3,199
Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,587	1,595
Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,579	1,604
Other Assets [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		33	64
Other Assets [Member] | Options/Futures contracts on notes and bonds
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		26	18
Other Assets [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[2]	0	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		5	33
Other Assets [Member] | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		8	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]	30	30
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(128)	(115)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options/Futures contracts on notes and bonds
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(30)	(24)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[2]	(45)	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(2)	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(47)	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		(82)	(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.