Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Available For Sale Securities [Abstract]
Less than 12 months, fair value	$ 1,427	$ 676
Less than 12 months, unrealized losses	(225)	(8)
12 months or longer, fair value	189	55
12 months or longer, unrealized losses	(48)	(1)
Total available-for-sale, fair value	1,616	731
Total available-for-sale, unrealized losses	(273)	(9)
U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	307	161
Less than 12 months, unrealized losses	(36)	(1)
12 months or longer, fair value	14	16
12 months or longer, unrealized losses	(3)	(1)
Total available-for-sale, fair value	321	177
Total available-for-sale, unrealized losses	(39)	(2)
State and municipal bonds [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	95	11
Less than 12 months, unrealized losses	(11)	0
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	(1)	0
Total available-for-sale, fair value	96	11
Total available-for-sale, unrealized losses	(12)	0
Foreign Government Debt [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	18	3
Less than 12 months, unrealized losses	(4)	0
12 months or longer, fair value	0	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	18	3
Total available-for-sale, unrealized losses	(4)	0
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	597	270
Less than 12 months, unrealized losses	(134)	(5)
12 months or longer, fair value	74	8
12 months or longer, unrealized losses	(28)	0
Total available-for-sale, fair value	671	278
Total available-for-sale, unrealized losses	(162)	(5)
Residential Mortgage Backed Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	127	94
Less than 12 months, unrealized losses	(13)	(1)
12 months or longer, fair value	55	1
12 months or longer, unrealized losses	(12)	0
Total available-for-sale, fair value	182	95
Total available-for-sale, unrealized losses	(25)	(1)
Residential Mortgage Backed Non Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	102	3
Less than 12 months, unrealized losses	(19)	0
12 months or longer, fair value	0	1
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	102	4
Total available-for-sale, unrealized losses	(19)	0
Commercial Mortgage Backed Securities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	11	2
Less than 12 months, unrealized losses	(1)	0
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	12	2
Total available-for-sale, unrealized losses	(1)	0
Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	67	60
Less than 12 months, unrealized losses	(3)	0
12 months or longer, fair value	43	29
12 months or longer, unrealized losses	(4)	0
Total available-for-sale, fair value	110	89
Total available-for-sale, unrealized losses	(7)	0
Other Asset Backed [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	103	72
Less than 12 months, unrealized losses	(4)	(1)
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	104	72
Total available-for-sale, unrealized losses	$ (4)	$ (1)