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, 2025	Dec. 31, 2024
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		$ 4,563	$ 3,959
Options/Futures/Forward contracts on notes and bonds
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		768	449
Convertible securities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[1]	14	12
Investment And Embedded Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		54	53
Fair Value, Liability		(294)	(303)
Derivative, Notional Amount		5,345	4,420
Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[2]	921	1,047
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		132	146
Fair Value, Liability		(101)	116
Derivative, Notional Amount		4,831	4,475
Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,906	1,579
Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		2,925	2,896
Other derivative instruments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		265	211
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,186	1,258
Other Assets [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		38	41
Other Assets [Member] | Options/Futures/Forward contracts on notes and bonds
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		2	0
Other Assets [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[2]	2	35
Other Assets [Member] | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		93	103
Other Assets [Member] | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		39	43
Other Assets [Member] | Other derivative instruments
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		3	0
Other Assets [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		5	35
Fixed Maturities [Member] | Convertible securities
Derivatives, Fair Value [Line Items]
Derivative Asset, Not Subject to Master Netting Arrangement	[1]	14	12
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(289)	(295)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options/Futures/Forward contracts on notes and bonds
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(5)	(8)
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] | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(1)	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(100)	(116)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other derivative instruments
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(5)	(2)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(5)	(2)
Equity Securities | Convertible securities
Derivatives, Fair Value [Line Items]
Derivative Liability, Not Subject to Master Netting Arrangement	[1]	$ 0	$ 0

[1] Includes fair value of embedded derivatives.

[2] Related to MRB book of business.