Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Available For Sale Securities [Abstract]
Less than 12 months, fair value	$ 1,165	$ 676
Less than 12 months, unrealized losses	(177)	(8)
12 months or longer, fair value	323	55
12 months or longer, unrealized losses	(66)	(1)
Total, fair value	1,488	731
Tota, unrealized losses	(243)	(9)
U.S. Treasury and government agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	266	161
Less than 12 months, unrealized losses	(34)	(1)
12 months or longer, fair value	29	16
12 months or longer, unrealized losses	(4)	(1)
Total, fair value	295	177
Tota, unrealized losses	(38)	(2)
State and municipal bonds [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	92	11
Less than 12 months, unrealized losses	(10)	0
12 months or longer, fair value	1	0
12 months or longer, unrealized losses	(1)	0
Total, fair value	93	11
Tota, unrealized losses	(11)	0
Foreign Governments [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	9	3
Less than 12 months, unrealized losses	(3)	0
12 months or longer, fair value	0	0
12 months or longer, unrealized losses	0	0
Total, fair value	9	3
Tota, unrealized losses	(3)	0
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	508	270
Less than 12 months, unrealized losses	(106)	(5)
12 months or longer, fair value	141	8
12 months or longer, unrealized losses	(42)	0
Total, fair value	649	278
Tota, unrealized losses	(148)	(5)
Residential Mortgage backed Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	112	94
Less than 12 months, unrealized losses	(9)	(1)
12 months or longer, fair value	65	1
12 months or longer, unrealized losses	(13)	0
Total, fair value	177	95
Tota, unrealized losses	(22)	(1)
Residential Mortgage backed Non Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	65	3
Less than 12 months, unrealized losses	(10)	0
12 months or longer, fair value	2	1
12 months or longer, unrealized losses	(1)	0
Total, fair value	67	4
Tota, unrealized losses	(11)	0
Commercial mortgage backed Securities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	18	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, fair value	19	2
Tota, unrealized losses	(1)	0
Collateralized debt obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	51	60
Less than 12 months, unrealized losses	(1)	0
12 months or longer, fair value	60	29
12 months or longer, unrealized losses	(4)	0
Total, fair value	111	89
Tota, unrealized losses	(5)	0
Other asset backed [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	44	72
Less than 12 months, unrealized losses	(3)	(1)
12 months or longer, fair value	24	0
12 months or longer, unrealized losses	(1)	0
Total, fair value	68	72
Tota, unrealized losses	$ (4)	$ (1)