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Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
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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 | $ 121 | $ 106
Less than 12 months, unrealized losses | (3) | (4)
12 months or longer, fair value | 612 | 634
12 months or longer, unrealized losses | (136) | (156)
Total, fair value | 733 | 740
Tota, unrealized losses | (139) | (160)
U.S. Treasury And Government Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 3 | 41
Less than 12 months, unrealized losses | 0 | (1)
12 months or longer, fair value | 119 | 123
12 months or longer, unrealized losses | (13) | (18)
Total, fair value | 122 | 164
Tota, unrealized losses | (13) | (19)
State and municipal bonds [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 6 | 15
Less than 12 months, unrealized losses | 0 | (1)
12 months or longer, fair value | 63 | 63
12 months or longer, unrealized losses | (9) | (10)
Total, fair value | 69 | 78
Tota, unrealized losses | (9) | (11)
Foreign Governments [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 1 | 5
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 5 | 5
12 months or longer, unrealized losses | (2) | (2)
Total, fair value | 6 | 10
Tota, unrealized losses | (2) | (2)
Corporate Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 24 | 25
Less than 12 months, unrealized losses | (3) | (1)
12 months or longer, fair value | 285 | 302
12 months or longer, unrealized losses | (95) | (105)
Total, fair value | 309 | 327
Tota, unrealized losses | (98) | (106)
Residential Mortgage backed Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 5
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 98 | 100
12 months or longer, unrealized losses | (14) | (16)
Total, fair value | 98 | 105
Tota, unrealized losses | (14) | (16)
Residential Mortgage Backed Non Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 6
Less than 12 months, unrealized losses | 0 | (1)
12 months or longer, fair value | 6 | 21
12 months or longer, unrealized losses | (1) | (4)
Total, fair value | 6 | 27
Tota, unrealized losses | (1) | (5)
Commercial mortgage backed Securities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 0 |
Less than 12 months, unrealized losses | 0 |
12 months or longer, fair value | 6 |
12 months or longer, unrealized losses | 0 |
Total, fair value | 6 |
Tota, unrealized losses | 0 |
Collateralized debt obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 29 | 6
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 2 | 8
12 months or longer, unrealized losses | 0 | 0
Total, fair value | 31 | 14
Tota, unrealized losses | 0 | 0
Other asset backed [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 58 | 3
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 28 | 12
12 months or longer, unrealized losses | (2) | (1)
Total, fair value | 86 | 15
Tota, unrealized losses | $ (2) | $ (1)

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