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Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		$ (116)	$ (101)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease)		21	31
Debt Securities, Available-for-sale, Gain (Loss), Total		(97)	49
Foreign exchange		(65)	(131)
Gain (Loss) on Derivative		28	(140)
Other		(2)	(8)
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-Sale, Realized Gain		38	16
Debt Securities, Available-for-Sale, Realized Loss		96	141
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease)		8	40
Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell	[1]	(7)	(34)
Other Investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		(40)	168
Equity Securities
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)		63	3
Private equities
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		11	31
Equity securities, Private equities and Other investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		34	202
Other investments - Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		(53)
Reserved alternative investment fund
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)		53
Investment and embedded derivative instruments
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative		(23)	(43)
Other derivative instruments
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative		$ (3)	$ (2)
[1] Relates to certain securities we intended to sell and securities written to market entering default.

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Amount of credit impairment charges recognized in net realized investment gains (losses) on debt securities where no previous allowance for credit losses has been recorded, but for which the Company intends to sell the securities.

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Section 50
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