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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, 2022 | Dec. 31, 2021
--- | --- | ---
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | $ 1,427 | $ 676
Less than 12 months, unrealized losses | (225) | (8)
12 months or longer, fair value | 189 | 55
12 months or longer, unrealized losses | (48) | (1)
Total available-for-sale, fair value | 1,616 | 731
Total available-for-sale, unrealized losses | (273) | (9)
U S Treasury And Government [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 307 | 161
Less than 12 months, unrealized losses | (36) | (1)
12 months or longer, fair value | 14 | 16
12 months or longer, unrealized losses | (3) | (1)
Total available-for-sale, fair value | 321 | 177
Total available-for-sale, unrealized losses | (39) | (2)
State and municipal bonds [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 95 | 11
Less than 12 months, unrealized losses | (11) | 0
12 months or longer, fair value | 1 | 0
12 months or longer, unrealized losses | (1) | 0
Total available-for-sale, fair value | 96 | 11
Total available-for-sale, unrealized losses | (12) | 0
Foreign Government Debt [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 18 | 3
Less than 12 months, unrealized losses | (4) | 0
12 months or longer, fair value | 0 | 0
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 18 | 3
Total available-for-sale, unrealized losses | (4) | 0
Corporate Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 597 | 270
Less than 12 months, unrealized losses | (134) | (5)
12 months or longer, fair value | 74 | 8
12 months or longer, unrealized losses | (28) | 0
Total available-for-sale, fair value | 671 | 278
Total available-for-sale, unrealized losses | (162) | (5)
Residential Mortgage Backed Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 127 | 94
Less than 12 months, unrealized losses | (13) | (1)
12 months or longer, fair value | 55 | 1
12 months or longer, unrealized losses | (12) | 0
Total available-for-sale, fair value | 182 | 95
Total available-for-sale, unrealized losses | (25) | (1)
Residential Mortgage Backed Non Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 102 | 3
Less than 12 months, unrealized losses | (19) | 0
12 months or longer, fair value | 0 | 1
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 102 | 4
Total available-for-sale, unrealized losses | (19) | 0
Commercial Mortgage Backed Securities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 11 | 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 available-for-sale, fair value | 12 | 2
Total available-for-sale, unrealized losses | (1) | 0
Collateralized Debt Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 67 | 60
Less than 12 months, unrealized losses | (3) | 0
12 months or longer, fair value | 43 | 29
12 months or longer, unrealized losses | (4) | 0
Total available-for-sale, fair value | 110 | 89
Total available-for-sale, unrealized losses | (7) | 0
Other Asset Backed [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 103 | 72
Less than 12 months, unrealized losses | (4) | (1)
12 months or longer, fair value | 1 | 0
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 104 | 72
Total available-for-sale, unrealized losses | $ (4) | $ (1)

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