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Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | $ 348 | $ 1,165
Less than 12 months, unrealized losses | (12) | (177)
12 months or longer, fair value | 1,054 | 323
12 months or longer, unrealized losses | (245) | (66)
Total, fair value | 1,402 | 1,488
Tota, unrealized losses | (257) | (243)
U.S. Treasury and government agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 64 | 266
Less than 12 months, unrealized losses | (3) | (34)
12 months or longer, fair value | 196 | 29
12 months or longer, unrealized losses | (38) | (4)
Total, fair value | 260 | 295
Tota, unrealized losses | (41) | (38)
State and municipal bonds [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 48 | 92
Less than 12 months, unrealized losses | (3) | (10)
12 months or longer, fair value | 54 | 1
12 months or longer, unrealized losses | (12) | (1)
Total, fair value | 102 | 93
Tota, unrealized losses | (15) | (11)
Foreign Governments [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 5 | 9
Less than 12 months, unrealized losses | 0 | (3)
12 months or longer, fair value | 8 | 0
12 months or longer, unrealized losses | (4) | 0
Total, fair value | 13 | 9
Tota, unrealized losses | (4) | (3)
Corporate Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 192 | 508
Less than 12 months, unrealized losses | (5) | (106)
12 months or longer, fair value | 500 | 141
12 months or longer, unrealized losses | (153) | (42)
Total, fair value | 692 | 649
Tota, unrealized losses | (158) | (148)
Residential Mortgage backed Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 13 | 112
Less than 12 months, unrealized losses | 0 | (9)
12 months or longer, fair value | 132 | 65
12 months or longer, unrealized losses | (26) | (13)
Total, fair value | 145 | 177
Tota, unrealized losses | (26) | (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 | 22 | 2
12 months or longer, unrealized losses | (7) | (1)
Total, fair value | 25 | 67
Tota, unrealized losses | (7) | (11)
Commercial mortgage backed Securities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 11 | 18
Less than 12 months, unrealized losses | (1) | (1)
12 months or longer, fair value | 7 | 1
12 months or longer, unrealized losses | 0 | 0
Total, fair value | 18 | 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 | 101 | 60
12 months or longer, unrealized losses | (2) | (4)
Total, fair value | 110 | 111
Tota, unrealized losses | (2) | (5)
Other asset backed [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 3 | 44
Less than 12 months, unrealized losses | 0 | (3)
12 months or longer, fair value | 34 | 24
12 months or longer, unrealized losses | (3) | (1)
Total, fair value | 37 | 68
Tota, unrealized losses | $ (3) | $ (4)

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