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v3.23.3

Investments - Gross Unrealized losses by Major Security (Detail) $ in Millions | Sep. 30, 2023 USD ($) security | Dec. 31, 2022 USD ($) security | Sep. 30, 2022 USD ($) security
--- | --- | --- | ---
Number of Securities |  |  |
Total | security | 1,531 | 1,468 | 1,522
Less than 12 Months | security | 353 | 873 | 1,223
12 Months or Greater | security | 1,178 | 595 | 299
Fair Value |  |  |
Total | $ 54,926.2 | $ 44,315.9 | $ 43,030.1
Less than 12 Months | 22,483.5 | 28,119.4 | 32,956.5
12 Months or Greater | 32,442.7 | 16,196.5 | 10,073.6
Unrealized Losses |  |  |
Total | (3,846.3) | (3,551.5) | (3,943.1)
Less than 12 Months | (668.1) | (1,505.0) | (2,550.4)
12 Months or Greater | $ (3,178.2) | $ (2,046.5) | $ (1,392.7)
U.S. government obligations |  |  |
Number of Securities |  |  |
Total | security | 173 | 160 | 157
Less than 12 Months | security | 37 | 90 | 103
12 Months or Greater | security | 136 | 70 | 54
Fair Value |  |  |
Total | $ 34,293.8 | $ 24,802.5 | $ 22,385.4
Less than 12 Months | 16,686.2 | 17,327.2 | 16,085.8
12 Months or Greater | 17,607.6 | 7,475.3 | 6,299.6
Unrealized Losses |  |  |
Total | (2,098.4) | (1,604.7) | (1,855.4)
Less than 12 Months | (557.6) | (699.2) | (1,095.6)
12 Months or Greater | $ (1,540.8) | $ (905.5) | $ (759.8)
State and local government obligations |  |  |
Number of Securities |  |  |
Total | security | 356 | 348 | 353
Less than 12 Months | security | 46 | 239 | 292
12 Months or Greater | security | 310 | 109 | 61
Fair Value |  |  |
Total | $ 2,033.9 | $ 1,948.8 | $ 1,911.0
Less than 12 Months | 359.6 | 1,124.2 | 1,363.1
12 Months or Greater | 1,674.3 | 824.6 | 547.9
Unrealized Losses |  |  |
Total | (203.3) | (202.9) | (215.4)
Less than 12 Months | (7.6) | (76.8) | (129.8)
12 Months or Greater | $ (195.7) | $ (126.1) | $ (85.6)
Foreign government obligations |  |  |
Number of Securities |  |  |
Total | security | 1 | 1 | 1
Less than 12 Months | security | 0 | 0 | 1
12 Months or Greater | security | 1 | 1 | 0
Fair Value |  |  |
Total | $ 15.4 | $ 15.5 | $ 15.3
Less than 12 Months | 0.0 | 0.0 | 15.3
12 Months or Greater | 15.4 | 15.5 | 0.0
Unrealized Losses |  |  |
Total | (1.5) | (1.3) | (1.4)
Less than 12 Months | 0.0 | 0.0 | (1.4)
12 Months or Greater | $ (1.5) | $ (1.3) | $ 0.0
Corporate debt securities |  |  |
Number of Securities |  |  |
Total | security | 467 | 422 | 452
Less than 12 Months | security | 164 | 285 | 391
12 Months or Greater | security | 303 | 137 | 61
Fair Value |  |  |
Total | $ 9,490.0 | $ 8,449.6 | $ 8,885.6
Less than 12 Months | 3,380.4 | 5,717.6 | 7,875.5
12 Months or Greater | 6,109.6 | 2,732.0 | 1,010.1
Unrealized Losses |  |  |
Total | (591.8) | (676.1) | (832.5)
Less than 12 Months | (94.1) | (426.1) | (699.0)
12 Months or Greater | $ (497.7) | $ (250.0) | $ (133.5)
Residential mortgage-backed securities |  |  |
Number of Securities |  |  |
Total | security | 40 | 45 | 44
Less than 12 Months | security | 2 | 27 | 34
12 Months or Greater | security | 38 | 18 | 10
Fair Value |  |  |
Total | $ 99.9 | $ 151.0 | $ 165.1
Less than 12 Months | 0.4 | 65.1 | 126.0
12 Months or Greater | 99.5 | 85.9 | 39.1
Unrealized Losses |  |  |
Total | (13.0) | (17.5) | (16.5)
Less than 12 Months | 0.0 | (6.8) | (11.8)
12 Months or Greater | $ (13.0) | $ (10.7) | $ (4.7)
Commercial mortgage-backed securities |  |  |
Number of Securities |  |  |
Total | security | 196 | 226 | 234
Less than 12 Months | security | 0 | 99 | 182
12 Months or Greater | security | 196 | 127 | 52
Fair Value |  |  |
Total | $ 3,960.8 | $ 4,651.1 | $ 5,074.3
Less than 12 Months | 0.0 | 1,702.0 | 3,856.0
12 Months or Greater | 3,960.8 | 2,949.1 | 1,218.3
Unrealized Losses |  |  |
Total | (723.9) | (784.0) | (747.4)
Less than 12 Months | 0.0 | (192.1) | (425.4)
12 Months or Greater | $ (723.9) | $ (591.9) | $ (322.0)
Other asset-backed securities |  |  |
Number of Securities |  |  |
Total | security | 295 | 262 | 277
Less than 12 Months | security | 104 | 130 | 217
12 Months or Greater | security | 191 | 132 | 60
Fair Value |  |  |
Total | $ 5,001.8 | $ 4,247.8 | $ 4,544.8
Less than 12 Months | 2,056.9 | 2,144.8 | 3,597.1
12 Months or Greater | 2,944.9 | 2,103.0 | 947.7
Unrealized Losses |  |  |
Total | (210.1) | (260.5) | (268.9)
Less than 12 Months | (8.8) | (100.9) | (183.4)
12 Months or Greater | $ (201.3) | $ (159.6) | $ (85.5)
Redeemable preferred stocks |  |  |
Number of Securities |  |  |
Total | security | 3 | 4 | 4
Less than 12 Months | security | 0 | 3 | 3
12 Months or Greater | security | 3 | 1 | 1
Fair Value |  |  |
Total | $ 30.6 | $ 49.6 | $ 48.6
Less than 12 Months | 0.0 | 38.5 | 37.7
12 Months or Greater | 30.6 | 11.1 | 10.9
Unrealized Losses |  |  |
Total | (4.3) | (4.5) | (5.6)
Less than 12 Months | 0.0 | (3.1) | (4.0)
12 Months or Greater | $ (4.3) | $ (1.4) | $ (1.6)

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