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Schedule III Supplementary Insurance Information (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Supplementary Insurance Information, by Segment |  |  |  |
Deferred Acquisition Costs |  | $ 2,920.3 | $ 2,842.8 |
Reserves for Future Policy Contract Benefits |  | 38,017.0 | 36,806.4 |
Policyholder Account Balances |  | 5,636.4 | 5,633.7 |
Unearned Premiums |  | 412.8 | 384.0 |
Premium Income |  | 10,831.0 | 10,497.4 | $ 10,046.0
Net Investment Income | [1] | 2,032.7 | 2,130.0 | 2,096.7
Benefits and Change in Reserves for Future Benefits | [2] | 8,065.3 | 6,917.9 | 7,257.1
Amortization of Deferred Acquisition Costs |  | 527.1 | 521.0 | 481.4
All Other Expenses | [3] | 3,549.6 | 3,197.1 | 3,007.3
Amortization of Deferred Loss on Reinsurance |  | 116.7 | 41.4 | 44.1
Accelerated Charitable Contribution |  | 20.0 | 0.0 | 0.0
Settlement Loss on the U.S. Pension Plan Annuity Purchase |  | 103.8 | 0.0 | 0.0
Loss on Legal Settlement |  |  | 15.3 |
Pension Plan | UNITED STATES |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Settlement Loss on the U.S. Pension Plan Annuity Purchase |  | 103.8 | 0.0 | 0.0
Unum US |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Deferred Acquisition Costs |  | 1,208.7 | 1,260.6 |
Reserves for Future Policy Contract Benefits |  | 8,493.4 | 8,669.7 |
Policyholder Account Balances |  | 665.7 | 675.7 |
Unearned Premiums |  | 48.7 | 51.7 |
Premium Income |  | 7,083.5 | 6,883.2 | 6,579.2
Net Investment Income | [1] | 604.2 | 632.2 | 639.9
Benefits and Change in Reserves for Future Benefits | [2] | 4,120.4 | 3,864.7 | 3,808.5
Amortization of Deferred Acquisition Costs |  | 283.3 | 292.5 | 267.6
All Other Expenses | [3] | 2,115.2 | 2,011.3 | 1,879.2
Premiums Written | [4] | 4,947.5 | 4,834.0 | 4,634.3
Reserve Assumption Updates |  | 147.7 | 143.6 | 128.8
Unum International |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Deferred Acquisition Costs |  | 72.1 | 53.0 |
Reserves for Future Policy Contract Benefits |  | 2,404.3 | 2,163.0 |
Policyholder Account Balances |  | 0.0 | 0.0 |
Unearned Premiums |  | 201.5 | 165.5 |
Premium Income |  | 1,082.8 | 949.5 | 825.2
Net Investment Income | [1] | 145.6 | 128.8 | 137.2
Benefits and Change in Reserves for Future Benefits | [2] | 767.4 | 656.7 | 579.8
Amortization of Deferred Acquisition Costs |  | 10.7 | 9.5 | 8.4
All Other Expenses | [3] | 300.3 | 263.4 | 235.6
Premiums Written | [4] | 613.6 | 581.6 | 544.4
Reserve Assumption Updates |  | 5.4 | (7.5) | (17.9)
Colonial Life |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Deferred Acquisition Costs |  | 1,639.5 | 1,529.2 |
Reserves for Future Policy Contract Benefits |  | 2,032.0 | 1,904.2 |
Policyholder Account Balances |  | 858.9 | 862.5 |
Unearned Premiums |  | 46.9 | 45.4 |
Premium Income |  | 1,839.1 | 1,783.9 | 1,726.1
Net Investment Income | [1] | 172.6 | 161.5 | 153.5
Benefits and Change in Reserves for Future Benefits | [2] | 876.2 | 804.7 | 798.1
Amortization of Deferred Acquisition Costs |  | 233.1 | 219.0 | 205.4
All Other Expenses | [3] | 431.5 | 413.0 | 396.5
Premiums Written | [4] | 1,278.1 | 1,247.4 | 1,221.8
Reserve Assumption Updates |  | 8.9 | 46.0 | 80.7
Closed Block |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Deferred Acquisition Costs |  | 0.0 | 0.0 |
Reserves for Future Policy Contract Benefits |  | 25,087.3 | 24,069.5 |
Policyholder Account Balances |  | 4,111.8 | 4,095.5 |
Unearned Premiums |  | 115.7 | 121.4 |
Premium Income |  | 825.6 | 880.8 | 915.5
Net Investment Income | [1] | 1,016.5 | 1,148.9 | 1,066.3
Benefits and Change in Reserves for Future Benefits | [2] | 2,301.3 | 1,591.8 | 2,070.7
Amortization of Deferred Acquisition Costs |  | 0.0 | 0.0 | 0.0
All Other Expenses | [3] | 313.0 | 243.0 | 246.5
Premiums Written | [4] | 818.8 | 868.1 | 904.2
Reserve Assumption Updates |  | (640.5) | 175.3 | (368.8)
Corporate and Other Segment |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Premium Income |  | 0.0 | 0.0 | 0.0
Net Investment Income | [1] | 93.8 | 58.6 | 99.8
Benefits and Change in Reserves for Future Benefits | [2] | 0.0 | 0.0 | 0.0
Amortization of Deferred Acquisition Costs |  | 0.0 | 0.0 | 0.0
All Other Expenses | [3] | 389.6 | 266.4 | 249.5
Premiums Written | [4] | 0.0 | 0.0 | 0.0
Operating Segments |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Reserve Assumption Updates |  | (478.5) | 357.4 | (177.2)
Loss on Legal Settlement |  | 0.0 | 15.3 | 0.0
Operating Segments | Unum US |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Non-Contemporaneous Reinsurance |  | (1.0) |  |
Operating Segments | Closed Block |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |
Non-Contemporaneous Reinsurance |  | $ (28.6) | $ 25.1 | $ 34.8
[1] | Net investment income is allocated based upon segmentation. Each segment has its own specifically identified assets and receives the investment income generated by those assets.
[2] | Included in policy benefits including remeasurement loss or gain were the following: •In 2025, reserve assumption updates resulting in a net decrease in policy benefits including remeasurement gain or loss in the Unum US, Colonial Life and Unum International segments of $147.7 million, $8.9 million, $5.4 million, respectively, and a net increase in policy benefits including remeasurement gain or loss in the Closed Block segment of $640.5 million. •In 2024, reserve assumption updates resulting in a net decrease in policy benefits including remeasurement gain or loss in the Unum US, Colonial Life, and Closed Block segments of $143.6 million, $46.0 million, and $175.3 million, respectively, and a net increase in policy benefits including remeasurement gain or loss in the Unum International segment of $7.5 million. •In 2023, reserve assumption updates resulting in a net decrease in policy benefits including remeasurement gain or loss in the Unum US, and Colonial Life segments of $128.8 million and $80.7 million, r espectively, and a net increase in policy benefits including remeasurement gain or loss in the Unum International and Closed Block Segments of $17.9 million and $368.8 million, respectively. •In 2025, 2024, and 2023 the impact of non-contemporaneous reinsurance of $28.6 million, $25.1 million, and $34.8 million, respectively, in the Closed Block segment. In 2025, the impact of non-contemporaneous reinsurance of $1.0 million in the Unum US segment.
[3] | Includes commissions, interest and debt expense, deferral of acquisition costs, compensation expense, and other expenses. Where not directly attributable to a segment, expenses are generally allocated based on activity levels, time information, and usage statistics. Also included in all other expenses were the following: •In 2025, 2024 and 2023 the amortization of the cost of reinsurance of $116.7 million, $41.4 million, and $44.1 million respectively, in the Closed Block segment. •In 2025, we incurred an expense related to an accelerated charitable contribution of $20.0 million, in the Corporate segment. •In 2025, we incurred a settlement loss on the U.S. pension plan annuity purchase of $103.8 million, in the Corporate segment. •In 2024, we incurred a loss on legal settlement of $15.3 million for the settlement of an employment-related matter, in the Corporate segment.
[4] | Excludes life insurance

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