Investments (Amortized Cost And Fair Value Of Available-For-Sale and Held-To-Maturity Investment Portfolios) (Detail) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Available For Sale Securities [Abstract]
Investment, Type [Extensible Enumeration]	Fixed Maturities [Member]	Fixed Maturities [Member]
Total available-for-sale, amortized cost	$ 1,406	$ 1,464
Allowance for Credit Losess	0	0
Gross unrealized gains	2	7
Gross unrealized losses	(169)	(129)
Total available-for-sale, fair value	1,239	1,342
U.S. Treasury And Government Agency [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	462	478
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(15)	(10)
Total available-for-sale, fair value	447	468
US States And Political Subdivisions [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	104	106
Allowance for Credit Losess	0	0
Gross unrealized gains	1	3
Gross unrealized losses	(14)	(8)
Total available-for-sale, fair value	91	101
Foreign Governments [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	7	7
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(3)	(2)
Total available-for-sale, fair value	4	5
Corporate Obligations [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	469	462
Allowance for Credit Losess	0	0
Gross unrealized gains	0	1
Gross unrealized losses	(117)	(96)
Total available-for-sale, fair value	352	367
Residential Mortgage-Backed Agency [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	109	125
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(16)	(11)
Total available-for-sale, fair value	93	114
Residential Mortgage-Backed Non-Agency [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	16	17
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(1)	(1)
Total available-for-sale, fair value	15	16
Commercial Mortgage-Backed [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost		10
Allowance for Credit Losess		0
Gross unrealized gains		0
Gross unrealized losses		0
Total available-for-sale, fair value		10
Collateralized Debt Obligations [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	71	30
Allowance for Credit Losess	0	0
Gross unrealized gains	1	1
Gross unrealized losses	0	0
Total available-for-sale, fair value	72	31
Other Asset-Backed [Member] \| Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	168	229
Allowance for Credit Losess	0	0
Gross unrealized gains	0	2
Gross unrealized losses	(3)	(1)
Total available-for-sale, fair value	$ 165	$ 230

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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