Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Available For Sale Securities [Abstract]
Less than 12 months, fair value	$ 427	$ 1,165
Less than 12 months, unrealized losses	(13)	(177)
12 months or longer, fair value	1,051	323
12 months or longer, unrealized losses	(190)	(66)
Total, fair value	1,478	1,488
Tota, unrealized losses	(203)	(243)
U.S. Treasury and government agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	97	266
Less than 12 months, unrealized losses	(5)	(34)
12 months or longer, fair value	196	29
12 months or longer, unrealized losses	(29)	(4)
Total, fair value	293	295
Tota, unrealized losses	(34)	(38)
State and municipal bonds [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	52	92
Less than 12 months, unrealized losses	(2)	(10)
12 months or longer, fair value	35	1
12 months or longer, unrealized losses	(8)	(1)
Total, fair value	87	93
Tota, unrealized losses	(10)	(11)
Foreign Governments [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	1	9
Less than 12 months, unrealized losses	0	(3)
12 months or longer, fair value	9	0
12 months or longer, unrealized losses	(2)	0
Total, fair value	10	9
Tota, unrealized losses	(2)	(3)
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	195	508
Less than 12 months, unrealized losses	(4)	(106)
12 months or longer, fair value	509	141
12 months or longer, unrealized losses	(119)	(42)
Total, fair value	704	649
Tota, unrealized losses	(123)	(148)
Residential Mortgage backed Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	51	112
Less than 12 months, unrealized losses	(2)	(9)
12 months or longer, fair value	124	65
12 months or longer, unrealized losses	(19)	(13)
Total, fair value	175	177
Tota, unrealized losses	(21)	(22)
Residential Mortgage backed Non Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	0	65
Less than 12 months, unrealized losses	0	(10)
12 months or longer, fair value	33	2
12 months or longer, unrealized losses	(6)	(1)
Total, fair value	33	67
Tota, unrealized losses	(6)	(11)
Commercial mortgage backed Securities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	15	18
Less than 12 months, unrealized losses	0	(1)
12 months or longer, fair value	7	1
12 months or longer, unrealized losses	(1)	0
Total, fair value	22	19
Tota, unrealized losses	(1)	(1)
Collateralized debt obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	9	51
Less than 12 months, unrealized losses	0	(1)
12 months or longer, fair value	102	60
12 months or longer, unrealized losses	(3)	(4)
Total, fair value	111	111
Tota, unrealized losses	(3)	(5)
Other asset backed [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	7	44
Less than 12 months, unrealized losses	0	(3)
12 months or longer, fair value	36	24
12 months or longer, unrealized losses	(3)	(1)
Total, fair value	43	68
Tota, unrealized losses	$ (3)	$ (4)