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		Dec. 31, 2022		Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Future policy benefits		$ 10,120		$ 5,947
Foreign currency forward contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		4,134		6,182
Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,511		12,944
Convertible Securities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[1]	37		12
Investment And Embedded Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		5,682		19,138
Derivative Asset, Subject to Master Netting Arrangement, before Offset		112		69
Derivative Liability, Subject to Master Netting Arrangement, before Offset		(139)		(166)
Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[2]	939		905
Other
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		0		3
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		939		908
Guaranteed Minimum Income Benefit
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[3]	1,979		1,432
Derivative Asset, Subject to Master Netting Arrangement, before Offset	[3]	0		0
Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,595		0
Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,604		0
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		3,199		0
Derivative Asset, Subject to Master Netting Arrangement, before Offset		17		0
Derivative Liability, Subject to Master Netting Arrangement, before Offset		(53)		0
Accounts Payable and Accrued Liabilities [Member] | Foreign currency forward contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset		(115)		(139)
Accounts Payable and Accrued Liabilities [Member] | Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset		(24)		(27)
Accounts Payable and Accrued Liabilities [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset	[2]	0		(16)
Accounts Payable and Accrued Liabilities [Member] | Other
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset		0		0
Accounts Payable and Accrued Liabilities [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset		0		(16)
Accounts Payable and Accrued Liabilities [Member] | Guaranteed Minimum Income Benefit
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset	[3]	(736)		(745)
Accounts Payable and Accrued Liabilities [Member] | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset		0		0
Accounts Payable and Accrued Liabilities [Member] | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset		(53)		0
Other Assets [Member] | Foreign currency forward contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset		64		25
Other Assets [Member] | Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset		18		33
Other Assets [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	[2]	33		0
Other Assets [Member] | Other
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset		0		0
Other Assets [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset		33		0
Other Assets [Member] | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset		17		0
Other Assets [Member] | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset		0		0
Fixed Maturities [Member] | Convertible Securities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	[1]	30		11
Equity Securities [Member] | Convertible Securities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset	[1]	0		0
Guaranteed Minimum Income Benefit | Fair Value, Recurring [Member] | Level 3
Derivatives, Fair Value [Line Items]
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross		$ 736	[4],[5]	$ 745	[6]

[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

[4] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

[5] The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.

[6] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.