Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Available For Sale Securities [Abstract]
Less than 12 months, fair value	$ 676	$ 325
Less than 12 months, unrealized losses	(8)	(3)
12 months or longer, fair value	55	91
12 months or longer, unrealized losses	(1)	(2)
Total available-for-sale, fair value	731	416
Total available-for-sale, unrealized losses	(9)	(5)
U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	161	99
Less than 12 months, unrealized losses	(1)	(1)
12 months or longer, fair value	16	0
12 months or longer, unrealized losses	(1)	0
Total available-for-sale, fair value	177	99
Total available-for-sale, unrealized losses	(2)	(1)
State and municipal bonds [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	11
Less than 12 months, unrealized losses	0
12 months or longer, fair value	0
12 months or longer, unrealized losses	0
Total available-for-sale, fair value	11
Total available-for-sale, unrealized losses	0
Foreign Government Debt [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	3	2
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 available-for-sale, fair value	3	2
Total available-for-sale, unrealized losses	0	0
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	270	103
Less than 12 months, unrealized losses	(5)	(1)
12 months or longer, fair value	8	7
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	278	110
Total available-for-sale, unrealized losses	(5)	(1)
Residential Mortgage Backed Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	94	53
Less than 12 months, unrealized losses	(1)	(1)
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	95	53
Total available-for-sale, unrealized losses	(1)	(1)
Residential Mortgage Backed Non Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	3	2
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	1	1
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	4	3
Total available-for-sale, unrealized losses	0	0
Commercial Mortgage Backed Securities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	2	0
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	0	5
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	2	5
Total available-for-sale, unrealized losses	0	0
Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	60	37
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	29	78
12 months or longer, unrealized losses	0	(2)
Total available-for-sale, fair value	89	115
Total available-for-sale, unrealized losses	0	(2)
Other Asset Backed [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	72	29
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	72	29
Total available-for-sale, unrealized losses	$ (1)	$ 0