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, 2021	Dec. 31, 2020
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		$ 3,657	$ 2,807
Options/Futures contracts on notes, bonds, and equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		2,063	1,749
Convertible securities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[1]	13	11
Total investment and embedded derivative instruments
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		80	44
Fair Value, Liability		(79)	(52)
Derivative, Notional Amount		5,733	4,567
Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[2]	761	709
Other
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		52	16
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		813	725
Guaranteed Minimum Income Benefit [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[3]	0	0
Derivative, Notional Amount	[3]	1,506	1,658
Other Assets [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		21	22
Other Assets [Member] | Options/Futures contracts on notes, bonds, and equities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		48	13
Other Assets [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[2]	0	0
Other Assets [Member] | Other
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		2	0
Other Assets [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		2	0
Fixed Maturities [Member] | Convertible securities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	11	9
Equity Securities [Member] | Convertible securities
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[1]	0	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(69)	(49)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options/Futures contracts on notes, bonds, and equities
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(10)	(3)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[2]	(7)	(17)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other
Derivatives, Fair Value [Line Items]
Fair Value, Liability		0	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(7)	(17)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Guaranteed Minimum Income Benefit [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[3]	$ (760)	$ (1,089)

[1] Includes fair value of embedded derivatives.

[2] Related to GMDB and GLB book of business.

[3] Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.