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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		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		$ 283	$ 198	$ 327	$ 201
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease)		25	23	76	95
Debt Securities, Available-for-sale, Gain (Loss), Total		46	111	(58)	186
Foreign exchange		(115)	(58)	(269)	(162)
Other		2	(1)	(5)	(8)
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-Sale, Realized Gain		121	21	228	73
Debt Securities, Available-for-Sale, Realized Loss		157	91	376	338
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease)		22	48	21	80
Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell	[1]	(22)	(19)	(34)	(81)
Other Investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		82	152	103	452
Equity Securities
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)		396	123	596	147
Private equities
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		48	(41)	31	39
Other investments - Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)		(116)		(116)
Reserved alternative investment fund
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)		66		131
Investment and embedded derivative instruments
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative		(85)	66	46	6
Other derivative instruments
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative		$ (9)	$ (2)	$ (14)	$ (7)
[1] Relates to certain securities we intend 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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