Fair Value of Financial Instruments - Additional Information (Detail) $ in Millions	6 Months Ended
Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	$ 45,233	$ 46,781
Period end valuation	0
U.S. corporate
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	$ 26,813	27,985
Non-U.S. corporate
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	7,636	7,811
Level 2 \| Other invested assets \| Nonrecurring fair value
Fair Value of Financial Instruments [Line Items]
Real estate owned	$ 24	$ 23
Level 2 \| Fixed maturity securities \| Third-Party Pricing Services
Fair Value of Financial Instruments [Line Items]
Percentage of available for sale debt securities	88.00%
Level 2 \| Fixed maturity securities \| Third-Party Pricing Services \| U.S. corporate
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	$ 23,287
Level 2 \| Fixed maturity securities \| Third-Party Pricing Services \| Non-U.S. corporate
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	5,976
Level 2 \| Fixed maturity securities \| Internal models \| U.S. corporate
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	1,542
Level 2 \| Fixed maturity securities \| Internal models \| Non-U.S. corporate
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	849
Level 3 \| Fixed maturity securities \| Internal models
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	2,781
Level 3 \| Fixed maturity securities \| Broker Quotes
Fair Value of Financial Instruments [Line Items]
Available-for-sale debt securities	$ 205
Fair Value Measured at Net Asset Value Per Share \| Limited Partnerships \| Maximum
Fair Value of Financial Instruments [Line Items]
Liquidation period	10 years
Contractual period	12 years
Fair Value Measured at Net Asset Value Per Share \| Limited Partnerships \| Minimum
Fair Value of Financial Instruments [Line Items]
Liquidation period	5 years
Contractual period	10 years

Fair Value of Financial Instruments [Line Items]

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- Definition

Percent of total fixed maturity securities portfolio priced using third-party pricing sources in determining fair value.

+ References

No definition available.

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The valuation of financial futures at the end of the period as a result of settling the margins on these contracts on a daily basis.

+ References

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Publisher FASB
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- Definition

Remaining period of expected liquidation by investee of underlying asset of investment measured at net asset value per share or unit. In 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
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Period when redemption restriction has been in effect for investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure), in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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- Definition

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-3

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-Topic 310
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