Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Available For Sale Securities [Abstract]
Less than 12 months, fair value	$ 1,611	$ 676
Less than 12 months, unrealized losses	(168)	(8)
12 months or longer, fair value	124	55
12 months or longer, unrealized losses	(19)	(1)
Total available-for-sale, fair value	1,735	731
Total available-for-sale, unrealized losses	(187)	(9)
U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	318	161
Less than 12 months, unrealized losses	(27)	(1)
12 months or longer, fair value	19	16
12 months or longer, unrealized losses	(3)	(1)
Total available-for-sale, fair value	337	177
Total available-for-sale, unrealized losses	(30)	(2)
State and municipal bonds [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	53	11
Less than 12 months, unrealized losses	(7)	0
12 months or longer, fair value	0	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	53	11
Total available-for-sale, unrealized losses	(7)	0
Foreign Government Debt [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	15	3
Less than 12 months, unrealized losses	(4)	0
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	16	3
Total available-for-sale, unrealized losses	(4)	0
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	732	270
Less than 12 months, unrealized losses	(105)	(5)
12 months or longer, fair value	25	8
12 months or longer, unrealized losses	(7)	0
Total available-for-sale, fair value	757	278
Total available-for-sale, unrealized losses	(112)	(5)
Residential Mortgage Backed Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	146	94
Less than 12 months, unrealized losses	(7)	(1)
12 months or longer, fair value	41	1
12 months or longer, unrealized losses	(7)	0
Total available-for-sale, fair value	187	95
Total available-for-sale, unrealized losses	(14)	(1)
Residential Mortgage Backed Non Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	118	3
Less than 12 months, unrealized losses	(11)	0
12 months or longer, fair value	1	1
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	119	4
Total available-for-sale, unrealized losses	(11)	0
Commercial Mortgage Backed Securities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	16	2
Less than 12 months, unrealized losses	(1)	0
12 months or longer, fair value	0	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	16	2
Total available-for-sale, unrealized losses	(1)	0
Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	81	60
Less than 12 months, unrealized losses	(3)	0
12 months or longer, fair value	36	29
12 months or longer, unrealized losses	(2)	0
Total available-for-sale, fair value	117	89
Total available-for-sale, unrealized losses	(5)	0
Other Asset Backed [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	132	72
Less than 12 months, unrealized losses	(3)	(1)
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	133	72
Total available-for-sale, unrealized losses	$ (3)	$ (1)