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Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
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Available For Sale Securities [Abstract] |  |
Investment, Type [Extensible Enumeration] | Fixed Maturities [Member] | Fixed Maturities [Member]
Less than 12 months, fair value | $ 58 | $ 1,165
Less than 12 months, unrealized losses | (1) | (177)
12 months or longer, fair value | 796 | 323
12 months or longer, unrealized losses | (139) | (66)
Total, fair value | 854 | 1,488
Tota, unrealized losses | (140) | (243)
U.S. Treasury And Government Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 11 | 266
Less than 12 months, unrealized losses | 0 | (34)
12 months or longer, fair value | 143 | 29
12 months or longer, unrealized losses | (18) | (4)
Total, fair value | 154 | 295
Tota, unrealized losses | (18) | (38)
State and municipal bonds [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 23 | 92
Less than 12 months, unrealized losses | (1) | (10)
12 months or longer, fair value | 57 | 1
12 months or longer, unrealized losses | (7) | (1)
Total, fair value | 80 | 93
Tota, unrealized losses | (8) | (11)
Foreign Governments [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 9
Less than 12 months, unrealized losses | 0 | (3)
12 months or longer, fair value | 6 | 0
12 months or longer, unrealized losses | (2) | 0
Total, fair value | 6 | 9
Tota, unrealized losses | (2) | (3)
Corporate Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 17 | 508
Less than 12 months, unrealized losses | 0 | (106)
12 months or longer, fair value | 337 | 141
12 months or longer, unrealized losses | (90) | (42)
Total, fair value | 354 | 649
Tota, unrealized losses | (90) | (148)
Residential Mortgage backed Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 112
Less than 12 months, unrealized losses | 0 | (9)
12 months or longer, fair value | 118 | 65
12 months or longer, unrealized losses | (14) | (13)
Total, fair value | 118 | 177
Tota, unrealized losses | (14) | (22)
Residential Mortgage Backed Non Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 3 | 65
Less than 12 months, unrealized losses | 0 | (10)
12 months or longer, fair value | 21 | 2
12 months or longer, unrealized losses | (5) | (1)
Total, fair value | 24 | 67
Tota, unrealized losses | (5) | (11)
Commercial mortgage backed Securities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 4 | 18
Less than 12 months, unrealized losses | 0 | (1)
12 months or longer, fair value | 3 | 1
12 months or longer, unrealized losses | 0 | 0
Total, fair value | 7 | 19
Tota, unrealized losses | 0 | (1)
Collateralized debt obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 51
Less than 12 months, unrealized losses | 0 | (1)
12 months or longer, fair value | 89 | 60
12 months or longer, unrealized losses | (1) | (4)
Total, fair value | 89 | 111
Tota, unrealized losses | (1) | (5)
Other asset backed [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 44
Less than 12 months, unrealized losses | 0 | (3)
12 months or longer, fair value | 22 | 24
12 months or longer, unrealized losses | (2) | (1)
Total, fair value | 22 | 68
Tota, unrealized losses | $ (2) | $ (4)

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