Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Available For Sale Securities [Abstract]
Investment, Type [Extensible Enumeration]	Fixed Maturities [Member]	Fixed Maturities [Member]
Less than 12 months, fair value	$ 228	$ 53
Less than 12 months, unrealized losses	(1)	(2)
12 months or longer, fair value	545	593
12 months or longer, unrealized losses	(135)	(127)
Total, fair value	773	646
Tota, unrealized losses	(136)	(129)
U.S. Treasury And Government Agency [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	12	2
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	95	122
12 months or longer, unrealized losses	(10)	(10)
Total, fair value	107	124
Tota, unrealized losses	(10)	(10)
State and municipal bonds [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	12	4
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	54	63
12 months or longer, unrealized losses	(9)	(8)
Total, fair value	66	67
Tota, unrealized losses	(9)	(8)
Foreign Governments [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	0	0
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	5	5
12 months or longer, unrealized losses	(2)	(2)
Total, fair value	5	5
Tota, unrealized losses	(2)	(2)
Corporate Obligations [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	47	9
Less than 12 months, unrealized losses	0	(2)
12 months or longer, fair value	287	283
12 months or longer, unrealized losses	(101)	(94)
Total, fair value	334	292
Tota, unrealized losses	(101)	(96)
Residential Mortgage backed Agency [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	10	5
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	87	90
12 months or longer, unrealized losses	(11)	(11)
Total, fair value	97	95
Tota, unrealized losses	(11)	(11)
Residential Mortgage Backed Non Agency [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	5	5
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	5	5
12 months or longer, unrealized losses	(1)	(1)
Total, fair value	10	10
Tota, unrealized losses	(1)	(1)
Commercial mortgage backed Securities [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	1	0
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	0	3
12 months or longer, unrealized losses	0	0
Total, fair value	1	3
Tota, unrealized losses	0	0
Collateralized debt obligations [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	62	8
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	0	0
12 months or longer, unrealized losses	0	0
Total, fair value	62	8
Tota, unrealized losses	0	0
Other asset backed [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	79	20
Less than 12 months, unrealized losses	(1)	0
12 months or longer, fair value	12	22
12 months or longer, unrealized losses	(1)	(1)
Total, fair value	91	42
Tota, unrealized losses	$ (2)	$ (1)

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Indicates type of investment. Includes, but is not limited to, common stock, preferred stock, convertible security, fixed income security, government security, option purchased, warrant, loan participation and assignment, commercial paper, bankers' acceptance, certificates of deposit, short-term security, repurchase agreement, and other investment company.

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