Unum (UNM) 10-Q 30 Oct 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Oct. 28, 2024
Entity Information
Document Type	10-Q
Document Quarterly Report	true
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Transition Report	false
Entity File Number	001-11294
Entity Registrant Name	Unum Group
Entity Central Index Key	0000005513
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	62-1598430
Entity Address, Address Line One	1 Fountain Square
Entity Address, City or Town	Chattanooga,
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	37402
City Area Code	423
Local Phone Number	294-1011
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		182,611,898
NEW YORK STOCK EXCHANGE, INC. | Common Class A
Entity Information
Trading Symbol	UNM
Security Exchange Name	NYSE
Title of 12(b) Security	Common stock, $0.10 par value
NEW YORK STOCK EXCHANGE, INC. | 6.250% Junior Subordinated Notes due 2058
Entity Information
Trading Symbol	UNMA
Security Exchange Name	NYSE
Title of 12(b) Security	6.250% Junior Subordinated Notes due 2058

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Investments
Fixed Maturity Securities - at fair value (amortized cost of $38,822.6; $38,410.6; allowance for credit losses of $2.9; $2.2)	$ 37,783.5	$ 36,833.9
Mortgage Loans (net of allowance for credit losses of $16.5; $10.2)	2,238.9	2,318.2
Policy Loans	3,625.6	3,620.2
Other Long-term Investments	1,682.8	1,579.4
Short-term Investments	1,990.8	1,610.7
Total Investments	47,321.6	45,962.4
Other Assets
Cash and Bank Deposits	163.4	146
Accounts and Premiums Receivable (net of allowance for credit losses of $27.1; $29.5)	1,495.7	1,543.7
Reinsurance Recoverable (net of allowance for credit losses of $1.7; $1.7)	8,637.6	9,108.4
Accrued Investment Income	786.8	633.9
Deferred Acquisition Costs	2,823.5	2,714.5
Goodwill	352	349.9
Property and Equipment	495.2	485.3
Deferred Income Tax	431.9	649.4
Other Assets	1,632.8	1,661.7
Total Assets	64,140.5	63,255.2
Liabilities
Future Policy Benefits	39,444.5	40,009.4
Policyholders' Account Balances	5,661.3	5,667.7
Unearned Premiums	474.7	380.2
Other Policyholders’ Funds	1,507.7	1,615.7
Income Tax Payable	137.7	190
Deferred Income Tax	28.5	27
Long-term Debt	3,470.4	3,430.4
Other Liabilities	2,464.3	2,283.4
Total Liabilities	53,189.1	53,603.8
Commitments and Contingent Liabilities - Note 13
Stockholders' Equity
Common Stock, $0.10 par; authorized: 725,000,000 shares; issued: 195,419,352 and 194,588,625 shares	19.5	19.4
Additional Paid-in Capital	1,563.3	1,547.8
Accumulated Other Comprehensive Loss	(2,729.7)	(3,308)
Retained Earnings	12,642.4	11,431.5
Treasury Stock - at cost: 10,918,177 and 1,216,528 shares	(544.1)	(39.3)
Total Stockholders' Equity	10,951.4	9,651.4
Total Liabilities and Stockholders' Equity	$ 64,140.5	$ 63,255.2

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Investments
Amortized Cost of Fixed Maturity Securities	$ 38,822.6	$ 38,410.6
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	2.9	2.2
Other Assets
Premium Receivable, Allowance for Credit Loss	27.1	29.5
Reinsurance Recoverable, Allowance for Credit Loss	$ 1.7	$ 1.7
Stockholders' Equity
Common Stock, Par Value (in dollars per share)	$ 0.10	$ 0.10
Common Stock, Shares Authorized	725,000,000	725,000,000
Common Stock, Shares Issued	195,419,352	194,588,625
Treasury Stock, Common, Shares	10,918,177	1,216,528

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue
Premium Income	$ 2,628.8	$ 2,525.9	$ 7,866.3	$ 7,494.3
Net Investment Income	527.8	526	1,586.4	1,565.9
Net Investment Loss	(12.9)	(31)	(24.5)	(30)
Other Income	73.3	71.6	222.5	210.6
Total Revenue	3,217	3,092.5	9,650.7	9,240.8
Benefits and Expenses
Policy Benefits	1,864.6	1,778.6	5,624.2	5,498.6
Policy Benefits - Remeasurement Loss (Gain)	(402.7)	168.4	(567.5)	(61.6)
Commissions	315.1	289.7	947.8	869.7
Interest and Debt Expense	49.2	48.6	148.6	145.6
Deferral of Acquisition Costs	(163.3)	(153.3)	(495.3)	(467.5)
Amortization of Deferred Acquisition Costs	133.8	129.1	387.9	358.7
Compensation Expense	294.2	297.9	895.9	867.3
Other Expenses	311.5	271.8	903.3	818.6
Total Benefits and Expenses	2,402.4	2,830.8	7,844.9	8,029.4
Income Before Income Tax	814.6	261.7	1,805.8	1,211.4
Income Tax
Current	95.6	187.5	315.8	381.7
Deferred	73.3	(127.8)	59.6	(123.5)
Total Income Tax	168.9	59.7	375.4	258.2
Net Income	$ 645.7	$ 202	$ 1,430.4	$ 953.2
Net Income Per Common Share
Basic	$ 3.46	$ 1.03	$ 7.54	$ 4.83
Assuming Dilution	$ 3.46	$ 1.02	$ 7.52	$ 4.81

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net Income	$ 645.7	$ 202	$ 1,430.4	$ 953.2
Other Comprehensive Income (Loss)
Change in Net Unrealized Loss on Securities (net of tax expense (benefit) of $327.6; $(313.8); $110.4; $(249.2))	1,232.6	(1,185.8)	427.9	(920)
Change in the Effect of Discount Rate Assumptions on the Liability for Future Policy Benefits, Net of Reinsurance (net of tax expense (benefit) of $(329.3); $445.0; $35.6; $368.2)	(1,239.3)	1,688.4	121.4	1,374.6
Change in Net Loss on Derivatives (net of tax expense (benefit) of $14.1; $(38.9); $(9.0); $(44.7))	55.7	(144.4)	(35.2)	(168.1)
Change in Foreign Currency Translation Adjustment (net of tax expense (benefit) of $—; $(0.7); $1.5; $0.3)	68.5	(55.1)	61.2	7.9
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense (benefit) of $(0.3); $1.2; $9.8; $1.1)	1	(3.9)	(3)	(3.3)
Net Other Comprehensive Income	116.5	307	578.3	297.7
Comprehensive Income	$ 762.2	$ 509	$ 2,008.7	$ 1,250.9

STATEMENT OF COMPREHENSIVE INCO

STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Other Comprehensive Income (Loss)
Change in Net Unrealized Gain on Securities After Adjustment, Tax Expense (Benefit)	$ 327.6	$ (313.8)	$ 110.4	$ (249.2)
OCI, Liability for Future Policy Benefit, Gain (Loss), after REclassification Adjustment, Tax	(329.3)	445	35.6	368.2
Change in Net Gain on Hedges, Tax Benefit	(14.1)	38.9	9	44.7
Change in Foreign Currency Translation Adjustment, Tax Expense	0	0.7	(1.5)	(0.3)
Change in Unrecognized Pension and Postretirement Benefit costs, Tax Expense	$ 0.3	$ (1.2)	$ (9.8)	$ (1.1)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total		Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock, Common
Balance at Beginning of Year at Dec. 31, 2022			$ 30.8	$ 2,441	$ (3,448.3)	$ 13,141.3	$ (3,429.8)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	13.3
Other Comprehensive Income	$ 297.7
Net Income	953.2					953.2
Dividends to Stockholders (per common share: $0.420; $0.365; $1.150; $1.025)						(205.8)
Cost of Shares Repurchased	175.4						175.4
Balance at End of Year at Sep. 30, 2023	9,618.1		30.9	2,454.3	(3,150.6)	13,888.7	(3,605.2)
Balance at Beginning of Year at Jun. 30, 2023			30.9	2,444.9	(3,457.6)	13,758.1	(3,530.4)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0	9.4
Other Comprehensive Income	307				307
Net Income	202					202
Dividends to Stockholders (per common share: $0.420; $0.365; $1.150; $1.025)						(71.4)
Cost of Shares Repurchased	74.8						74.8
Balance at End of Year at Sep. 30, 2023	9,618.1		30.9	2,454.3	(3,150.6)	13,888.7	(3,605.2)
Balance at Beginning of Year at Dec. 31, 2023	9,651.4		19.4	1,547.8	(3,308)	11,431.5	(39.3)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	15.5
Other Comprehensive Income	578.3				578.3
Net Income	1,430.4					1,430.4
Dividends to Stockholders (per common share: $0.420; $0.365; $1.150; $1.025)						(219.5)
Cost of Shares Repurchased	504.8	[1]					504.8
Balance at End of Year at Sep. 30, 2024	10,951.4		19.5	1,563.3	(2,729.7)	12,642.4	(544.1)
Balance at Beginning of Year at Jun. 30, 2024			19.5	1,558.8	(2,846.2)	12,074.6	(342.1)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0	4.5
Other Comprehensive Income	116.5				116.5
Net Income	645.7					645.7
Dividends to Stockholders (per common share: $0.420; $0.365; $1.150; $1.025)						(77.9)
Cost of Shares Repurchased	202	[1]					202
Balance at End of Year at Sep. 30, 2024	$ 10,951.4		$ 19.5	$ 1,563.3	$ (2,729.7)	$ 12,642.4	$ (544.1)
[1] 1

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.420	$ 0.365	$ 1.150	$ 1.025

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash Flows from Operating Activities
Net Income	$ 1,430.4	$ 953.2
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Change in Receivables	566.4	455.9
Deferred Policy Acquisition Cost	(107.4)	(108.8)
Change in Insurance Liabilities	(631)	(169.3)
Change in Income Taxes	21.9	(26.9)
Change in Other Accrued Liabilities	(58.3)	(150.2)
Non-cash Components of Net Investment Income	(327.9)	(262.9)
Net Investment Loss	24.5	30
Depreciation	89.9	80.9
Amortization of the Cost of Reinsurance	31.1	33.1
Other, Net	(12.2)	24.3
Net Cash Provided by Operating Activities	1,027.4	859.3
Cash Flows from Investing Activities
Proceeds from Sale of Debt Securities, Available-for-sale	356.5	1,013.5
Proceeds from Maturities of Fixed Maturity Securities	997.2	1,113.9
Proceeds from Sales and Maturities of Other Investments	234.8	275.2
Payments to Acquire Debt Securities, Available-for-sale	(1,550.9)	(2,439.4)
Purchases of Other Investments	(218.6)	(227.1)
Net Purchases of Short-term Investments	(307.9)	(45.2)
Net Increase (Decrease) in Payables for Collateral on Investments	189.5	(100.4)
Net Purchases of Property and Equipment	(93.7)	(89.1)
Net Cash Used by Investing Activities	(393.1)	(498.6)
Cash Flows from Financing Activities
Issuance of Long-term Debt	391.6	0
Repayments of Long-term Debt	350	0
Issuance of Common Stock	4.8	4.1
Repurchase of Common Stock	(500)	(174.2)
Dividends Paid to Stockholders	(219.3)	(205.7)
Proceeds from Policyholder Account Deposits	100.9	109.3
Payments for Policyholder Account Withdrawals	(65.5)	(65.2)
Cash Received Related to Active Life Volatility Cover Agreement	26.7	18.6
Other, Net	(6.1)	(0.9)
Net Cash Used by Financing Activities	(616.9)	(314)
Net Increase (Decrease) in Cash and Bank Deposits	17.4	46.7
Cash and Bank Deposits at Beginning of Year	146	119.2
Cash and Bank Deposits at End of Period	$ 163.4	$ 165.9

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	The accompanying consolidated financial statements of Unum Group and its subsidiaries (the Company) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. For further information, refer to the consolidated financial statements and footnotes included in our annual report on Form 10-K for the year ended December 31, 2023.

Accounting Developments

Accounting Developments	9 Months Ended
	Sep. 30, 2024
Accounting Developments and New Accounting Policies [Abstract]
Accounting Developments	Note 2 - Accounting Developments Accounting Standards Updates (ASUs) Adopted in 2023: ASU 2022-02, Financial Instruments - Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures The amendments in this update eliminated the troubled debt restructuring recognition and measurement guidance and instead required that an entity evaluate whether the modification represents a new loan or the continuation of an existing loan. The amendments also enhanced the disclosure requirements related to certain modifications of receivables made to borrowers experiencing financial difficulty. In addition, the amendments in this update required that an entity disclose current-period gross write-offs by year of origination for financing receivables and net investment in leases. The amendments in this update were applied prospectively in the period of adoption as of January 1, 2023. The adoption of this update modified our disclosures but did not have an impact on our financial position or results of operations. ASU 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts and related amendments This update significantly amended the accounting and disclosure requirements for long-duration insurance contracts. These changes included a requirement to review, and if necessary, update cash flow assumptions used to measure the liability for future policy benefits for traditional and limited-payment contracts at least annually, with changes recognized in earnings. In addition, an entity is required to update the discount rate assumption at each reporting date using a yield that is reflective of an upper-medium grade fixed-income instrument with changes recognized in other comprehensive income (loss) (OCI). These changes resulted in the elimination of the provision for risk of adverse deviation and premium deficiency (or loss recognition) testing for traditional long-duration insurance contracts. The update also required that an entity measure all market risk benefits associated with deposit contracts at fair value, with changes recognized in earnings except for the portion attributable to a change in the instrument-specific credit risk, which is to be recognized in OCI. This update also simplified the amortization of deferred acquisition costs by requiring amortization on a constant level basis over the expected term of the related contracts. Deferred acquisition costs are required to be written off for unexpected contract terminations, but are no longer subject to an impairment test. Significant additional disclosures are required, which include disaggregated rollforwards of certain liability balances and the disclosure of qualitative and quantitative information about expected cash flows, estimates, and assumptions. We do not have products with market risk benefits. We adopted this guidance effective January 1, 2023 using the modified retrospective approach with changes applied as of January 1, 2021, also referred to as the transition date. All historically reported information included in our consolidated financial statements and accompanying footnotes were adjusted as of the transition date to reflect the modified retrospective adoption of ASU 2018-12. Accounting Updates Outstanding: ASU 2020-04 , Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and related amendments The amendments in this update provide optional guidance, for a limited period of time, to ease the potential burden in accounting for and recognizing the effects of reference rate reform on financial reporting. The guidance allows for various practical expedients and exceptions when applying GAAP to contracts, hedging relationships, and other transactions affected either by discontinued rates as a direct result of reference rate reform or a market-wide change in interest rates used for discounting, margining or contract price alignment, if certain criteria are met. Specifically, the guidance provides certain practical expedients for contract modifications, fair value hedges, and cash flow hedges, and also provides certain exceptions related to changes in the critical terms of a hedging relationship. The guidance also allows for a one-time election to sell or transfer debt securities that were both classified as held-to-maturity prior to January 1, 2020 and reference a rate affected by the reform. The adoption of this update is permitted as of the beginning of the interim period that includes March 12, 2020 (the issuance date of the update), or any date thereafter, through December 31, 2024, at which point the guidance will sunset. We have elected practical expedients for contracts impacted by reference rate reform which did not result in a material impact on our financial position or results of operations. We will continue to monitor our contracts and hedging relationships throughout the adoption period. ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures The amendments in this update enhance disclosures of significant expenses for reportable segments. Specifically, the update adds a requirement to disclose significant expenses that are regularly provided to the Chief Operating Decision Maker (CODM) and are included in each reported measure of segment profit or loss. This update will require the disclosure of the title and position of the CODM as well as an explanation of how they use the reported measure(s) to assess segment performance and make decisions about allocating resources. The update also requires the disclosure of the amount and composition of other segment items, which is the difference between reported segment revenues less the significant segment expenses. The amendments in this update allow for the disclosure of more than one measure of segment profit or loss, provided that at least one of the reported measures includes the segment profit or loss measure that is most consistent with GAAP measurement principles. We will adopt this update effective for the annual period ended December 31, 2024 and for the interim period beginning January 1, 2025 using a retrospective approach. The adoption of this update will not have an impact on our financial position or results of operations, but will expand our disclosures effective for the annual period ended December 31, 2024 and subsequent interim periods. ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures The amendments in this update require greater disaggregation of income tax disclosures related to the income tax rate reconciliation and income taxes paid. Specifically, the guidance requires additional information that meet a quantitative threshold in specified categories with respect to the reconciliation of the effective tax rate to the statutory tax rate for federal, state, and foreign income taxes. The specified categories are the following: state and local income taxes, foreign tax effects, effect of cross-border tax laws, enactment of new tax laws, nontaxable or nondeductible items, tax credits, changes in valuation allowances, and changes in unrecognized tax benefits. The quantitative threshold for each category is five percent of the amount computed by multiplying income (or loss) from continuing operations before income taxes by the statutory federal income tax rate. In addition, the amendments require additional information pertaining to income taxes paid, net of refunds, to be disaggregated by federal, state and foreign jurisdictions, and further disaggregated for specific jurisdictions to the extent the related amounts exceed a quantitative threshold of five percent of total income taxes paid. The amendments also require disclosures of income (or loss) before income tax expense (or benefit) as domestic or foreign for each annual reporting period. The amendments eliminate the historic requirement to disclose information regarding unrecognized tax benefits having a reasonable possibility of significantly increasing or decreasing in the twelve months following the reporting date, as well as the requirement to disclose the cumulative temporary differences when a deferred tax liability is not recognized due to certain exceptions under ASC 740. We will adopt this update effective for the annual period beginning January 1, 2025. The adoption of this update is permitted on a prospective basis or a retrospective basis. The adoption of this update will not have an impact on our financial position or results of operations, but will expand our disclosures effective for the annual period beginning January 1, 2025.

Fair Values of Financial Instru

Fair Values of Financial Instruments	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Values of Financial Instruments	Fair Value of Financial Instruments Fair Value Measurements for Financial Instruments Carried at Fair Value We report fixed maturity securities, which are classified as available-for-sale securities, derivative financial instruments, and unrestricted equity securities at fair value in our consolidated balance sheets. We report our investments in private equity partnerships at our share of the partnerships' net asset value per share or its equivalent (NAV) as a practical expedient for fair value. The degree of judgment utilized in measuring the fair value of financial instruments generally correlates to the level of pricing observability. Financial instruments with readily available active quoted prices or for which fair value can be measured from actively quoted prices in active markets generally have more pricing observability and less judgment utilized in measuring fair value. An active market for a financial instrument is a market in which transactions for an asset or a similar asset occur with sufficient frequency and volume to provide pricing information on an ongoing basis. A quoted price in an active market provides the most reliable evidence of fair value and should be used to measure fair value whenever available. Conversely, financial instruments rarely traded or not quoted have less observability and are measured at fair value using valuation techniques that require more judgment. Pricing observability is generally impacted by a number of factors, including the type of financial instrument, whether the financial instrument is new to the market and not yet established, the characteristics specific to the transaction, and overall market conditions. We classify financial instruments in accordance with a fair value hierarchy consisting of three levels based on the observability of valuation inputs: • Level 1 - the highest category of the fair value hierarchy classification wherein inputs are unadjusted and represent quoted prices in active markets for identical assets or liabilities at the measurement date. • Level 2 - valued using inputs (other than prices included in Level 1) that are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument's anticipated life. • Level 3 - the lowest category of the fair value hierarchy and reflects the judgment of management regarding what market participants would use in pricing assets or liabilities at the measurement date. Financial assets and liabilities categorized as Level 3 are generally those that are valued using unobservable inputs to extrapolate an estimated fair value. Valuation Methodologies of Financial Instruments Measured at Fair Value Valuation techniques used for assets and liabilities accounted for at fair value are generally categorized into three types. The market approach uses prices and other relevant information from market transactions involving identical or comparable assets or liabilities. The income approach converts future amounts, such as cash flows or earnings, to a single present amount, or a discounted amount. The cost approach is based upon the amount that currently would be required to replace the service capacity of an asset, or the current replacement cost. We use valuation techniques that are appropriate in the circumstances and for which sufficient data are available that can be obtained without undue cost and effort. In some cases, a single valuation technique will be appropriate (for example, when valuing an asset or liability using quoted prices in an active market for identical assets or liabilities). In other cases, multiple valuation techniques will be appropriate. If we use multiple valuation techniques to measure fair value, we evaluate and weigh the results, as appropriate, considering the reasonableness of the range indicated by those results. A fair value measurement is the point within that range that is most representative of fair value in the circumstances. The selection of the valuation method(s) to apply considers the definition of an exit price and depends on the nature of the asset or liability being valued. For assets and liabilities accounted for at fair value, we generally use valuation techniques consistent with the market approach, and to a lesser extent, the income approach. We believe the market approach provides more observable data than the income approach, considering the type of investments we hold. Our fair value measurements could differ significantly based on the valuation technique and available inputs. When using a pricing service, we obtain the vendor's pricing documentation to ensure we understand their methodologies. We periodically review and approve the selection of our pricing vendors to ensure we are in agreement with their current methodologies. When markets are less active, brokers may rely more on models with inputs based on the information available only to the broker. Our internal investment management professionals, which include portfolio managers and analysts, monitor securities priced by brokers and evaluate their prices for reasonableness based on benchmarking to available primary and secondary market information. In weighing a broker quote as an input to fair value, we place less reliance on quotes that do not reflect the result of market transactions. We also consider the nature of the quote, particularly whether it is a bid or market quote. If prices in an inactive market do not reflect current prices for the same or similar assets, adjustments may be necessary to arrive at fair value. When relevant market data is unavailable, which may be the case during periods of market uncertainty, the income approach can, in suitable circumstances, provide a more appropriate fair value. During 2024, we have applied valuation approaches and techniques on a consistent basis to similar assets and liabilities and consistent with those approaches and techniques used at year end 2023. Fixed Maturity and Equity Securities We use observable and unobservable inputs in measuring the fair value of our fixed maturity and equity securities. For securities categorized as Level 1, fair values equal active Trade Reporting and Compliance Engine (TRACE) pricing or unadjusted market maker prices. For securities categorized as Level 2 or Level 3, inputs that may be used in valuing each class of securities at any given time period are disclosed below. Actual inputs used to determine fair values will vary for each reporting period depending on the availability of inputs which may, at times, be affected by the lack of market liquidity. Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs United States Government and Government Agencies and Authorities Valuation Method Principally the market approach Not applicable Valuation Techniques / Inputs Prices obtained from external pricing services Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs States, Municipalities, and Political Subdivisions Valuation Method Principally the market approach Principally the market approach Valuation Techniques / Inputs Prices obtained from external pricing services Analysis of similar bonds, adjusted for comparability Relevant reports issued by analysts and rating agencies Audited financial statements Foreign Governments Valuation Method Principally the market approach Principally the market approach Valuation Techniques / Inputs Prices obtained from external pricing services Analysis of similar bonds, adjusted for comparability Non-binding broker quotes Call provisions Public Utilities Valuation Method Principally the market and income approaches Principally the market and income approaches Valuation Techniques / Inputs Prices obtained from external pricing services Change in benchmark reference Non-binding broker quotes Analysis of similar bonds, adjusted for comparability Benchmark yields Discount for size - illiquidity Transactional data for new issuances and secondary trades Volatility of credit Security cash flows and structures Lack of marketability Recent issuance / supply Audited financial statements Security and issuer level spreads Security creditor ratings/maturity/capital structure/optionality Public covenants Comparative bond analysis Relevant reports issued by analysts and rating agencies Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs Mortgage/Asset-Backed Securities Valuation Method Principally the market and income approaches Principally the market approach Valuation Techniques / Inputs Prices obtained from external pricing services Analysis of similar bonds, adjusted for comparability Non-binding broker quotes Prices obtained from external pricing services Security cash flows and structures Underlying collateral Prepayment speeds/loan performance/delinquencies Relevant reports issued by analysts and rating agencies Audited financial statements All Other Corporate Bonds Valuation Method Principally the market and income approaches Principally the market and income approaches Valuation Techniques / Inputs Prices obtained from external pricing services Change in benchmark reference Non-binding broker quotes Discount for size - illiquidity Benchmark yields Volatility of credit Transactional data for new issuances and secondary trades Lack of marketability Security cash flows and structures Prices obtained from external pricing services Recent issuance / supply Security and issuer level spreads Security creditor ratings/maturity/capital structure/optionality Public covenants Comparative bond analysis Relevant reports issued by analysts and rating agencies Audited financial statements Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs Redeemable Preferred Stocks Valuation Method Principally the market approach Principally the market approach Valuation Techniques / Inputs Non-binding broker quotes Financial statement analysis Benchmark yields Comparative bond analysis Call provisions Relevant reports issued by analysts and rating agencies Audited financial statements Perpetual Preferred and Equity Securities Valuation Method Principally the market approach Principally the market and income approaches Valuation Techniques / Inputs Prices obtained from external pricing services Financial statement analysis Non-binding broker quotes The management of our investment portfolio includes establishing pricing policy and reviewing the reasonableness of sources and inputs used in developing pricing. We review all prices that vary between multiple pricing vendors by a threshold that is outside a normal market range for the asset type. In the event we receive a vendor's market price that does not appear reasonable based on our market analysis, we may challenge the price and request further information about the assumptions and methodologies used by the vendor to price the security. We may change the selected price based on a better data source such as an actual trade. We also review all prices that did not change from the prior month to ensure that these prices are within our expectations. The overall valuation process for determining fair values may include adjustments to valuations obtained from our pricing sources when they do not represent a valid exit price. These adjustments may be made when, in our judgment and considering our knowledge of the financial conditions and industry in which the issuer operates, certain features of the financial instrument require that an adjustment be made to the value originally obtained from our pricing sources. These features may include the complexity of the financial instrument, the market in which the financial instrument is traded, counterparty credit risk, credit structure, concentration, or liquidity. Additionally, an adjustment to the price derived from a model typically reflects our judgment of the inputs that other participants in the market for the financial instrument being measured at fair value would consider in pricing that same financial instrument. In the event an asset is sold, we test the validity of the fair value determined by our valuation techniques by comparing the selling price to the fair value determined for the asset in the immediately preceding month end reporting period. Certain of our investments do not have readily determinable market prices and/or observable inputs or may at times be affected by the lack of market liquidity. For these securities, we use internally prepared valuations, including valuations based on estimates of future profitability, to estimate the fair value. Additionally, we may obtain prices from independent third-party brokers to aid in establishing valuations for certain of these securities. Key assumptions used by us to determine fair value for these securities include risk free interest rates, risk premiums, performance of underlying collateral (if any), and other factors involving significant assumptions which may or may not reflect those of an active market. The parameters and inputs used to validate a price on a security may be adjusted for assumptions about risk and current market conditions on a quarter to quarter basis, as certain features may be more significant drivers of valuation at the time of pricing. Changes to inputs in valuations are not changes to valuation methodologies; rather, the inputs are modified to reflect direct or indirect impacts on asset classes from changes in market conditions. At September 30, 2024, approximately 21.1 percent of our fixed maturity securities were valued using active trades from TRACE pricing or broker market maker prices for which there was current market activity in that specific security (comparable to receiving one binding quote). The prices obtained were not adjusted, and the assets were classified as Level 1. The remaining 78.9 percent of our fixed maturity securities were valued based on non-binding quotes or other observable and unobservable inputs, as discussed below: • 62.8 percent of our fixed maturity securities were valued based on prices from pricing services that generally use observable inputs such as prices for securities or comparable securities in active markets in their valuation techniques. These assets were classified as Level 2. • 15.6 percent of our fixed maturity securities were valued based on one or more non-binding broker quotes, if validated by observable market data. When only one price is available, it is used if observable inputs and analysis confirms that it is appropriate. These assets, for which we were able to validate the price using other observable market data, were classified as Level 2. • 0.5 percent of our fixed maturity securities were valued based on prices of comparable securities, internal models, or pricing services or other non-binding quotes with no other observable market data. These assets were classified as either Level 2 or Level 3, with the categorization dependent on whether there was other observable market data. Derivatives Fair values for derivatives other than embedded derivatives in modified coinsurance arrangements are based on market quotes or pricing models and represent the net amount of cash we would have paid or received if the contracts had been settled or closed as of the last day of the period. Credit risk related to the counterparty and the Company is considered in determining the fair values of these derivatives. However, since we have collateralization agreements in place with each counterparty which limits our exposure, any credit risk is immaterial. Therefore, we determined that no adjustments for credit risk were required as of September 30, 2024 or December 31, 2023. Fair values for our embedded derivative in a modified coinsurance arrangement are estimated using internal pricing models and represent the hypothetical value of the duration mismatch of assets and liabilities, interest rate risk, and third party credit risk embedded in the modified coinsurance arrangement. We consider transactions in inactive markets to be less representative of fair value. We use all available observable inputs when measuring fair value, but when significant unobservable inputs are used, we classify these assets or liabilities as Level 3. Private Equity Partnerships Our private equity partnerships represent funds that are primarily invested in private credit, private equity, and real assets, as described below. Distributions received from the funds arise from income generated by the underlying investments as well as the liquidation of the underlying investments. There is generally not a public market for these investments. The following tables present additional information about our private equity partnerships, including commitments for additional investments which may or may not be funded: September 30, 2024 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 246.3 Not redeemable $ 126.1 50.7 Quarterly / 90 days notice 6.2 Total Private Credit 297.0 132.3 Private Equity (b) 574.8 Not redeemable 417.2 33.3 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 13.2 Total Private Equity 608.1 430.4 Real Assets (c) 488.8 Not redeemable 242.9 34.1 Quarterly / 90 days notice — Total Real Assets 522.9 242.9 Total Partnerships $ 1,428.0 $ 805.6 December 31, 2023 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 239.1 Not redeemable $ 128.2 44.5 Quarterly / 90 days notice 8.6 Total Private Credit 283.6 136.8 Private Equity (b) 543.9 Not redeemable 410.6 28.0 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 16.6 Total Private Equity 571.9 427.2 Real Assets (c) 437.5 Not redeemable 239.1 33.2 Quarterly / 90 days notice — Total Real Assets 470.7 239.1 Total Partnerships $ 1,326.2 $ 803.1 (a) Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North America and, to a lesser extent, outside of North America. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 80 percent in the next 3 years, 12 percent during the period from 3 to 5 years, and 8 percent during the period from 5 to 10 years. (b) Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 36 percent in the next 3 years, 31 percent during the period from 3 to 5 years, and 33 percent during the period from 5 to 10 years. (c) Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 38 percent in the next 3 years, 26 percent during period from 3 to 5 years, 34 percent during the period from 5 to 10 years, and 2 percent during the period from 10 to 15 years. We record changes in our share of net asset value of the partnerships in net investment income. We receive financial information related to our investments in partnerships and generally record investment income on a one-quarter lag in accordance with our accounting policy. Our partnerships are subject to transfer restrictions which extend over the life of the investment. There are no circumstances in which the transfer restrictions would lapse. The following tables present information about financial instruments measured at fair value on a recurring basis by fair value level, based on the observability of the inputs used: September 30, 2024 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ — $ 557.4 $ — $ — $ 557.4 States, Municipalities, and Political Subdivisions — 3,526.5 — — 3,526.5 Foreign Governments — 850.1 — — 850.1 Public Utilities 602.7 4,982.5 — — 5,585.2 Mortgage/Asset-Backed Securities — 799.6 51.0 — 850.6 All Other Corporate Bonds 7,362.2 19,015.8 28.0 — 26,406.0 Redeemable Preferred Stocks — 7.7 — — 7.7 Total Fixed Maturity Securities 7,964.9 29,739.6 79.0 — 37,783.5 Other Long-term Investments Derivatives Forwards — 49.5 — — 49.5 Foreign Currency Interest Rate Swaps — 56.0 — — 56.0 Embedded Derivative in Modified Coinsurance Arrangement — — 4.6 — 4.6 Total Derivatives — 105.5 4.6 — 110.1 Perpetual Preferred and Equity Securities — 0.1 21.7 — 21.8 Private Equity Partnerships — — — 1,428.0 1,428.0 Total Other Long-term Investments — 105.6 26.3 1,428.0 1,559.9 Total Financial Instrument Assets Carried at Fair Value $ 7,964.9 $ 29,845.2 $ 105.3 $ 1,428.0 $ 39,343.4 Liabilities Other Liabilities Derivatives Forwards $ — $ 95.2 $ — $ — $ 95.2 Foreign Currency Interest Rate Swaps — 35.0 — — 35.0 Total Derivatives — 130.2 — — 130.2 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 130.2 $ — $ — $ 130.2 December 31, 2023 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ — $ 624.8 $ — $ — $ 624.8 States, Municipalities, and Political Subdivisions — 3,678.4 — — 3,678.4 Foreign Governments — 890.7 — — 890.7 Public Utilities 301.3 5,020.3 — — 5,321.6 Mortgage/Asset-Backed Securities — 611.2 32.9 — 644.1 All Other Corporate Bonds 3,985.2 21,562.1 123.4 — 25,670.7 Redeemable Preferred Stocks — 3.6 — — 3.6 Total Fixed Maturity Securities 4,286.5 32,391.1 156.3 — 36,833.9 Other Long-term Investments Derivatives Forwards — 47.5 — — 47.5 Foreign Currency Interest Rate Swaps — 52.4 — — 52.4 Total Derivatives — 99.9 — — 99.9 Perpetual Preferred and Equity Securities — 10.3 21.6 — 31.9 Private Equity Partnerships — — — 1,326.2 1,326.2 Total Other Long-term Investments — 110.2 21.6 1,326.2 1,458.0 Total Financial Instrument Assets Carried at Fair Value $ 4,286.5 $ 32,501.3 $ 177.9 $ 1,326.2 $ 38,291.9 Liabilities Other Liabilities Derivatives Forwards $ — $ 78.0 $ — $ — $ 78.0 Foreign Currency Interest Rate Swaps — 38.2 — — 38.2 Embedded Derivative in Modified Coinsurance Arrangement — — 1.5 — 1.5 Total Derivatives — 116.2 1.5 — 117.7 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 116.2 $ 1.5 $ — $ 117.7 Changes in assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) are as follows: Three Months Ended September 30, 2024 Fair Value Beginning of Period Total Realized Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities Public Utilities $ — $ (0.2) $ 0.7 $ — $ (10.3) $ 9.8 $ — $ — $ — $ — Mortgage/Asset-Backed Securities 46.5 — 0.2 4.9 (0.7) 0.1 — 51.0 0.2 — All Other Corporate Bonds 53.3 — 2.0 — (42.2) 39.1 (24.2) 28.0 2.0 — Total Fixed Maturity Securities 99.8 (0.2) 2.9 4.9 (53.2) 49.0 (24.2) 79.0 2.2 — Perpetual Preferred and Equity Securities 21.7 — — — — — — 21.7 — — Embedded Derivative in Modified Coinsurance Arrangement 5.4 (0.8) — — — — — 4.6 — (0.8) Three Months Ended September 30, 2023 Fair Value Beginning of Period Total Realized and Unrealized Investment Gains (Losses) in Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities Public Utilities $ — $ (0.1) $ 0.1 $ — $ (3.9) $ 3.9 $ — $ — $ — $ — Mortgage/Asset-Backed Securities 24.1 — (1.4) 19.0 (1.0) 4.7 (0.2) 45.2 (1.4) — All Other Corporate Bonds 128.8 (4.6) 2.0 — (54.9) 87.5 (50.5) 108.3 2.0 — Total Fixed Maturity Securities 152.9 (4.7) 0.7 19.0 (59.8) 96.1 (50.7) 153.5 0.6 — Perpetual Preferred and Equity Securities 17.5 — — — — — — 17.5 — — Embedded Derivative in Modified Coinsurance Arrangement (8.4) 9.3 — — — — — 0.9 — 9.3 Nine Months Ended September 30, 2024 Fair Value Beginning of Year Total Realized Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities Public Utilities $ — $ (0.2) $ 0.3 $ — $ (10.3) $ 10.2 $ — $ — $ — $ — Mortgage/Asset-Backed Securities 32.9 — 0.6 15.5 (1.9) 3.9 — 51.0 0.6 — All Other Corporate Bonds 123.4 (2.6) 6.9 2.3 (196.4) 189.0 (94.6) 28.0 6.9 (2.6) Total Fixed Maturity Securities 156.3 (2.8) 7.8 17.8 (208.6) 203.1 (94.6) 79.0 7.5 (2.6) Perpetual Preferred and Equity Securities 21.6 0.1 — — — — — 21.7 — 0.1 Embedded Derivative in Modified Coinsurance Arrangement (1.5) 6.1 — — — — — 4.6 — 6.1 Nine Months Ended September 30, 2023 Fair Value Beginning of Year Total Realized and Unrealized Investment Gains (Losses) in Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities States, Municipalities, and Political Subdivisions $ 0.2 $ — $ — $ — $ — $ — $ (0.2) $ — $ — $ — Public Utilities — 0.1 (0.1) — (7.2) 7.2 — — — — Mortgage/Asset-Backed Securities 22.0 — (1.5) 29.9 (2.8) 6.6 (9.0) 45.2 (1.5) — All Other Corporate Bonds 158.7 (5.1) (20.6) 1.5 (229.8) 276.0 (72.4) 108.3 (20.6) — Total Fixed Maturity Securities 180.9 (5.0) (22.2) 31.4 (239.8) 289.8 (81.6) 153.5 (22.1) — Perpetual Preferred and Equity Securities 16.2 0.6 — 0.7 — — — 17.5 — 0.6 Embedded Derivative in Modified Coinsurance Arrangement (13.9) 14.8 — — — — — 0.9 — 14.8 Realized and unrealized investment gains and losses presented in the preceding tables represent gains and losses only for the time during which the applicable financial instruments were classified as Level 3. The transfers between levels resulted primarily from a change in observability of three inputs used to determine fair values of the securities transferred: (1) transactional data for new issuance and secondary trades, (2) broker/dealer quotes and pricing, primarily related to changes in the level of activity in the market and whether the market was considered orderly, and (3) comparable bond metrics from which to perform an analysis. For fair value measurements of financial instruments that were transferred either into or out of Level 3, we reflect the transfers using the fair value at the beginning of the period. We believe this allows for greater transparency, as all changes in fair value that arise during the reporting period of the transfer are disclosed as a component of our Level 3 reconciliation. The table below provides quantitative information regarding the significant unobservable inputs used in Level 3 fair value measurements derived from internal models. Unobservable inputs for fixed maturity securities are weighted by the fair value of the securities. Certain securities classified as Level 3 are excluded from the table below due to limitations in our ability to obtain the underlying inputs used by external pricing sources. September 30, 2024 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 16.3 Market Approach Volatility of Credit Market Convention (a) (b) 5.00% - 5.00% / 5.00% Priced at Par Value Perpetual Preferred and Equity Securities 21.7 Market Approach Market Convention (b) Priced at Cost, Owner's Equity, or Most Recent Round Embedded Derivative in Modified Coinsurance Arrangement 4.6 Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (c) Actuarial Assumptions (0.031)% December 31, 2023 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 15.9 Market Approach Volatility of Credit Market Convention (a) (b) 5.00% - 5.00% / 5.00% Priced at Par Value Perpetual Preferred and Equity Securities 21.6 Market Approach Market Convention (b) Priced at Cost, Owner's Equity, or Most Recent Round Embedded Derivative in Modified Coinsurance Arrangement (1.5) Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (c) Actuarial Assumptions 0.2% (a) Represents basis point adjustments for credit-specific factors (b) Represents a decision to price based on par value, cost, owner's equity, or the price of the most recent capital funding round when limited data is available (c) Represents various actuarial assumptions required to derive the liability cash flows. Fair value of embedded derivative is most often driven by the change in the weighted average credit spread to the swap curve for the assets backing the hypothetical loan Other than market convention, the impact of isolated decreases in unobservable inputs will result in a higher estimated fair value, whereas isolated increases in unobservable inputs will result in a lower estimated fair value. The unobservable input for market convention is not sensitive to input movements. The projected liability cash flows used in the fair value measurement of our Level 3 embedded derivative are based on expected claim payments. If claim payments increase, the projected liability cash flows will increase, resulting in a decrease in the fair value of the embedded derivative. Decreases in projected liability cash flows will result in an increase in the fair value of the embedded derivative. Fair Value Measurements for Financial Instruments Not Carried at Fair Value The methods and assumptions used to estimate fair values of financial instruments not carried at fair value are discussed as follows: Mortgage Loans: Fair value of newly originated, seasoned performing, or sub-performing but likely to continue cash flowing loans are calculated using a discounted cash flow analysis. Loans’ cash flows are modeled and appropriately discounted by a rate based on current yields and credit spreads. For sub and non-performing loans where there is some probability the loan will not continue to pay, a price based approach would be used to estimate the loan’s value in the open market utilizing current transaction information from similar loans. Policy Loans: Fair values for policy loans, net of reinsurance ceded, are estimated using discounted cash flow analyses and interest rates currently being offered to policyholders with similar policies. Carrying amounts for ceded policy loans, which equal $3,320.4 million and $3,322.5 million as of September 30, 2024 and December 31, 2023, respectively, approximate fair value and are reported on a gross basis in our consolidated balance sheets. A change in interest rates for ceded policy loans will not impact our financial position because the benefits and risks are fully ceded to reinsuring counterparties. Miscellaneous Long-term Investments: Carrying amounts for tax credit partnerships equal the unamortized balance of our contractual commitments and approximate fair value. Our shares of Federal Home Loan Bank (FHLB) common stock are carried at cost, which approximates fair value. Long-term Debt: Fair values for long-term debt are obtained from independent pricing services or discounted cash flow analyses based on current incremental borrowing rates for similar type

Investments

Investments	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	65% <= 75% 481.6 21.5 707.0 30.5 > 75% <= 85% 148.5 6.6 136.5 5.9 > 85% 81.8 3.7 64.8 2.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property There were no gross write-offs for the periods ending September 30, 2024 or December 31, 2023. The following tables present the amortized cost of our mortgage loans by year of origination and internal quality indicators at September 30, 2024 and December 31, 2023, respectively: September 30, 2024 Prior to 2020 2020 2021 2022 2023 2024 Total (in millions of dollars) Internal Mortgage Rating AA $ 88.1 $ — $ 6.4 $ — $ — $ — $ 94.5 A 684.4 92.6 145.0 24.3 38.0 — 984.3 BBB 710.4 63.1 181.1 63.8 29.0 23.1 1,070.5 BB 106.1 — — — — — 106.1 Total Amortized Cost 1,589.0 155.7 332.5 88.1 67.0 23.1 2,255.4 Allowance for credit losses (14.1) (0.5) (1.1) (0.3) (0.4) (0.1) (16.5) Carrying Amount $ 1,574.9 $ 155.2 $ 331.4 $ 87.8 $ 66.6 $ 23.0 $ 2,238.9 Loan-to-Value Ratio 1 <=65% $ 1,174.1 $ 113.7 $ 188.8 $ 15.6 $ 38.7 $ — $ 1,530.9 >65<=75% 231.2 33.9 94.9 72.5 28.3 23.1 483.9 >75%<=85% 122.6 8.1 20.3 — — — 151.0 >85% 61.1 — 28.5 — — — 89.6 Total Amortized Cost 1,589.0 155.7 332.5 88.1 67.0 23.1 2,255.4 Allowance for credit losses (14.1) (0.5) (1.1) (0.3) (0.4) (0.1) (16.5) Carrying Amount $ 1,574.9 $ 155.2 $ 331.4 $ 87.8 $ 66.6 $ 23.0 $ 2,238.9 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property December 31, 2023 Prior to 2019 2019 2020 2021 2022 2023 Total (in millions of dollars) Internal Mortgage Rating AA $ 74.3 $ 11.0 $ — $ — $ — $ — $ 85.3 A 589.0 100.3 94.1 100.1 23.2 38.0 944.7 BBB 618.4 224.8 71.4 248.0 64.4 29.2 1,256.2 BB 42.2 — — — — — 42.2 Total Amortized Cost 1,323.9 336.1 165.5 348.1 87.6 67.2 2,328.4 Allowance for credit losses (6.3) (1.3) (0.6) (1.0) (0.6) (0.4) (10.2) Carrying Amount $ 1,317.6 $ 334.8 $ 164.9 $ 347.1 $ 87.0 $ 66.8 $ 2,318.2 Loan-to-Value Ratio 1 <=65% $ 908.3 $ 197.7 $ 116.4 $ 145.2 $ 16.2 $ 30.0 $ 1,413.8 >65<=75% 252.1 138.4 40.8 171.0 71.4 37.2 710.9 >75%<=85% 97.3 — 8.3 31.9 — — 137.5 >85% 66.2 — — — — — 66.2 Total Amortized Cost 1,323.9 336.1 165.5 348.1 87.6 67.2 2,328.4 Allowance for credit losses (6.3) (1.3) (0.6) (1.0) (0.6) (0.4) (10.2) Carrying Amount $ 1,317.6 $ 334.8 $ 164.9 $ 347.1 $ 87.0 $ 66.8 $ 2,318.2 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property The following tables present a roll-forward of the allowance for expected credit losses by loan-to-value ratio for the three and nine months ended September 30, 2024 and 2023 : Three Months Ended September 30, 2024 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.7 $ 0.3 $ — $ — $ 4.0 >65<=75% 3.3 (1.1) — — 2.2 >75%<=85% 1.7 0.8 — — 2.5 >85% 3.4 4.4 — — 7.8 Total $ 12.1 $ 4.4 $ — $ — $ 16.5 Three Months Ended September 30, 2023 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.3 $ (0.1) $ — $ — $ 3.2 >65<=75% 4.8 (0.4) — — 4.4 >75%<=85% 0.9 — — — 0.9 >85% 2.1 (0.4) — — 1.7 Total $ 11.1 $ (0.9) $ — $ — $ 10.2 Nine Months Ended September 30, 2024 Beginning of Year Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.8 $ 0.2 $ — $ — $ 4.0 >65<=75% 3.8 (1.6) — — 2.2 >75%<=85% 1.2 1.3 — — 2.5 >85% 1.4 6.4 — — 7.8 Total $ 10.2 $ 6.3 $ — $ — $ 16.5 Nine Months Ended September 30, 2023 Beginning of Year Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.0 $ 0.2 $ — $ — $ 3.2 >65<=75% 4.7 (0.3) — — 4.4 >75%<=85% 1.1 (0.2) — — 0.9 >85% 0.5 1.2 — — 1.7 Total $ 9.3 $ 0.9 $ — $ — $ 10.2 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property During the three and nine months ended September 30, 2024, all commercial mortgage loans which were previously modified for borrowers experiencing financial difficulties were current. During the three and nine months ended September 30, 2023, we granted an other-than-insignificant payment delay for a commercial mortgage loan with an amortized cost of $14.2 million, which deferred the principal payment for 18 months. This modification represented less than one percent of the commercial mortgage loan portfolio balance. There were no troubled debt restructurings for the three and nine months ended September 30, 2024. At September 30, 2024 and December 31, 2023, we held no mortgage loans that were greater than 90 days past due regarding principal and/or interest payments. As of September 30, 2024 and December 31, 2023, we had no loan foreclosures. Other than our allowance for expected credit losses, we had no specifically identified impaired mortgage loans during the three and nine months ended September 30, 2024 or 2023, nor did we recognize any interest income on mortgage loans subsequent to impairment. At September 30, 2024, we had $28.5 million commitments to fund commercial mortgage loans. Consistent with how we determine the estimate of current expected credit losses for our funded mortgage loans each period, we estimate expected credit losses for loans that hav e not been funded but we are committed to fund at the end of each period. At September 30, 2024, we had $0.1 million of expected credit losses related to unfunded commitments on our consolidated balance sheets. At December 31, 2023, we had no expected credit losses related to unfunded commitments on our consolidated balance sheets. Investment Real Estate Our real estate held for the production of income balance was $60.8 million and $64.4 million at September 30, 2024 and December 31, 2023, respectively, and the associated accumulated depreciation was $130.8 million and $127.2 million at September 30, 2024 and December 31, 2023, respectively. We did not recognize any impairments related to our real estate during the three and nine months ended September 30, 2024. For the three and nine months ended September 30, 2023, we recognized a $3.0 million impairment related to certain of our real estate held for investment. Our held for sale real estate balance was $40.9 million at both September 30, 2024 and December 31, 2023 and the associated accumulated depreciation was $54.2 million at both September 30, 2024 and December 31, 2023. The estimated fair values less costs to sell are above the carrying values of the properties and we expect to close the sales of the properties within the next twelve months. Transfers of Financial Assets To manage our cash position more efficiently, we may enter into repurchase agreements with unaffiliated financial institutions. We generally use repurchase agreements as a means to finance the purchase of invested assets or for short-term general business purposes until projected cash flows become available from our operations or existing investments. Our repurchase agreements are typically outstanding for less than 30 days. We post collateral through our repurchase agreement transactions whereby the counterparty commits to purchase securities with the agreement to resell them to us at a later, specified date. The fair value of collateral posted is generally 102 percent of the cash received. Our investment policy also permits us to lend fixed maturity securities to unaffiliated financial institutions in short-term securities lending agreements. These agreements increase our investment income with minimal risk. Our securities lending policy requires that a minimum of 102 percent of the fair value of the securities loaned be maintained as collateral. We may receive cash and/or securities as collateral under these agreements. Cash received as collateral is typically reinvested in short-term investments. If securities are received as collateral, we are not permitted to sell or re-post them. As of September 30, 2024, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $57.9 million, for which we received collateral in the form of cash and securities of $25.8 million and $34.4 million, respectively. As of December 31, 2023, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $72.0 million, for which we received collateral in the form of cash and securities of $63.1 million and $12.5 million, respectively. We had no outstanding repurchase agreements at September 30, 2024 or December 31, 2023. The remaining contractual maturities of our securities lending agreements disaggregated by class of collateral pledged are as follows: September 30, 2024 December 31, 2023 Overnight and Continuous (in millions of dollars) Borrowings Public Utilities $ 3.7 $ 1.8 All Other Corporate Bonds 22.1 61.3 Total Borrowings 25.8 63.1 Gross Amount of Recognized Liability for Securities Lending Transactions 25.8 63.1 Amounts Related to Agreements Not Included in Offsetting Disclosure Contained Herein $ — $ — Certain of our U.S. insurance subsidiaries are members of regional FHLBs. Membership, which requires that we purchase a minimum amount of FHLB common stock on which we receive dividends, provides access to low-cost funding. Advances received from the FHLB are used for the purchase of fixed maturity securities. Additional common stock purchases may be required, based on the amount of funds we borrow from the FHLBs. The carrying value of common stock owned, collateral posted, and advances received are as follows: September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Value of FHLB Common Stock $ 25.6 $ 15.7 Advances from FHLB 299.0 64.5 Carrying Value of Collateral Posted to FHLB Fixed Maturity Securities $ 600.7 $ 589.0 Commercial Mortgage Loans 940.6 986.8 Total Carrying Value of Collateral Posted to FHLB $ 1,541.3 $ 1,575.8 Offsetting of Financial Instruments We enter into master netting agreements with each of our derivative's counterparties. These agreements provide for conditional rights of set-off upon the occurrence of an early termination event. An early termination event is considered a default, and it allows the non-defaulting party to offset its contracts in a loss position against any gain positions or payments due to the defaulting party. Under our agreements, default type events are defined as failure to pay or deliver as contractually agreed, misrepresentation, bankruptcy, or merger without assumption. See Note 5 for further discussion of collateral related to our derivative contracts. We have securities lending agreements with unaffiliated financial institutions that post collateral to us in return for the use of our fixed maturity securities. A right of set-off exists that allows us to keep and apply collateral received in the event of default by the counterparty. Default within a securities lending agreement would typically occur if the counterparty failed to return the securities borrowed from us as contractually agreed. In addition, if we default by not returning collateral received, the counterparty has a right of set-off against our securities or any other amounts due to us. Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties. September 30, 2024 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 105.5 $ — $ 105.5 $ (102.9) $ (2.3) $ 0.3 Securities Lending 57.9 — 57.9 (32.1) (25.8) — Total $ 163.4 $ — $ 163.4 $ (135.0) $ (28.1) $ 0.3 Financial Liabilities: Derivatives $ 130.2 $ — $ 130.2 $ (127.7) $ — $ 2.5 Securities Lending 25.8 — 25.8 (25.8) — — Total $ 156.0 $ — $ 156.0 $ (153.5) $ — $ 2.5 December 31, 2023 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 99.9 $ — $ 99.9 $ (91.9) $ (6.4) $ 1.6 Securities Lending 72.0 — 72.0 (8.9) (63.1) — Total $ 171.9 $ — $ 171.9 $ (100.8) $ (69.5) $ 1.6 Financial Liabilities: Derivatives $ 116.2 $ — $ 116.2 $ (109.4) $ — $ 6.8 Securities Lending 63.1 — 63.1 (63.1) — — Total $ 179.3 $ — $ 179.3 $ (172.5) $ — $ 6.8 Net Investment Income Net investment income reported in our consolidated statements of income is presented below. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Fixed Maturity Securities $ 465.4 $ 457.9 $ 1,388.5 $ 1,383.7 Derivatives 8.1 11.6 25.0 34.5 Mortgage Loans 22.0 22.9 66.6 69.8 Policy Loans 5.7 5.4 16.3 15.6 Other Long-term Investments Perpetual Preferred Securities 1 — 0.4 0.3 2.2 Private Equity Partnerships 2 19.6 22.6 72.6 56.7 Other 3.4 2.6 8.5 7.1 Short-term Investments 24.0 19.1 65.7 49.4 Gross Investment Income 548.2 542.5 1,643.5 1,619.0 Less Investment Expenses 17.5 13.5 48.3 44.0 Less Investment Income on Participation Fund Account Assets 2.9 3.0 8.8 9.1 Net Investment Income $ 527.8 $ 526.0 $ 1,586.4 $ 1,565.9 1 The net unrealized gain (loss) recognized in net investment income for the three months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was $0.2 million. The net unrealized gain (loss) recognized in net investment income for the nine months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was de minimis. The net unrealized gain (loss) recognized in net investment income for the three and nine months ended September 30, 2023 related to perpetual preferred securities still held at September 30, 2023 was $(0.4) million and $0.1 million, respectively. 2 The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2024 related to private equity partnerships" id="sjs-B4">Fixed Maturity Securities At September 30, 2024 and December 31, 2023, all fixed maturity securities were classified as available-for-sale. The amortized cost and fair values of securities by security type are shown as follows: September 30, 2024 Amortized Cost, Gross of ACL 1 ACL 1 Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 542.5 $ — $ 28.8 $ 13.9 $ 557.4 States, Municipalities, and Political Subdivisions 3,843.4 — 118.7 435.6 3,526.5 Foreign Governments 964.8 — 22.4 137.1 850.1 Public Utilities 5,561.8 — 272.3 248.9 5,585.2 Mortgage/Asset-Backed Securities 853.8 — 13.2 16.4 850.6 All Other Corporate Bonds 27,048.3 2.9 882.8 1,522.2 26,406.0 Redeemable Preferred Stocks 8.0 — — 0.3 7.7 Total Fixed Maturity Securities $ 38,822.6 $ 2.9 $ 1,338.2 $ 2,374.4 $ 37,783.5 December 31, 2023 Amortized Cost, Gross of ACL 1 ACL 1 Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 618.6 $ — $ 25.3 $ 19.1 $ 624.8 States, Municipalities, and Political Subdivisions 4,041.3 — 135.3 498.2 3,678.4 Foreign Governments 982.1 — 29.8 121.2 890.7 Public Utilities 5,398.2 — 217.1 293.7 5,321.6 Mortgage/Asset-Backed Securities 658.0 — 10.1 24.0 644.1 All Other Corporate Bonds 26,708.4 2.2 771.8 1,807.3 25,670.7 Redeemable Preferred Stocks 4.0 — — 0.4 3.6 Total Fixed Maturity Securities $ 38,410.6 $ 2.2 $ 1,189.4 $ 2,763.9 $ 36,833.9 1 Allowance for Credit Losses The following charts indicate the length of time our fixed maturity securities have been in a gross unrealized loss position. September 30, 2024 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 27.4 $ 0.3 $ 211.4 $ 13.6 States, Municipalities, and Political Subdivisions 145.0 2.5 2,061.0 433.1 Foreign Governments 50.5 1.7 320.5 135.4 Public Utilities 243.6 7.4 1,651.5 241.5 Mortgage/Asset-Backed Securities 81.3 0.2 304.3 16.2 All Other Corporate Bonds 1,013.2 9.6 13,185.8 1,512.6 Redeemable Preferred Stocks — — 3.7 0.3 Total Fixed Maturity Securities $ 1,561.0 $ 21.7 $ 17,738.2 $ 2,352.7 December 31, 2023 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 118.8 $ 0.7 $ 197.3 $ 18.4 States, Municipalities, and Political Subdivisions 128.0 4.0 2,035.1 494.2 Foreign Governments 149.9 3.3 312.9 117.9 Public Utilities 373.7 10.4 1,720.6 283.3 Mortgage/Asset-Backed Securities 60.3 2.5 316.7 21.5 All Other Corporate Bonds 1,483.8 26.8 14,215.2 1,780.5 Redeemable Preferred Stocks — — 3.6 0.4 Total Fixed Maturity Securities $ 2,314.5 $ 47.7 $ 18,801.4 $ 2,716.2 The following is a distribution of the maturity dates for fixed maturity securities. The maturity dates have not been adjusted for possible calls or prepayments. September 30, 2024 Amortized Cost, Net of ACL 1 Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 1,289.6 $ 2.6 $ 342.0 $ 5.5 $ 944.7 Over 1 year through 5 years 8,125.2 180.7 3,864.2 126.9 4,314.8 Over 5 years through 10 years 8,550.0 387.0 4,462.2 442.7 4,032.1 Over 10 years 20,001.1 754.7 9,350.9 1,782.9 9,622.0 37,965.9 1,325.0 18,019.3 2,358.0 18,913.6 Mortgage/Asset-Backed Securities 853.8 13.2 465.0 16.4 385.6 Total Fixed Maturity Securities $ 38,819.7 $ 1,338.2 $ 18,484.3 $ 2,374.4 $ 19,299.2 December 31, 2023 Amortized Cost, Net of ACL 1 Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 935.0 $ 0.9 $ 140.8 $ 7.5 $ 787.6 Over 1 year through 5 years 7,594.4 128.2 2,685.7 179.0 4,857.9 Over 5 years through 10 years 9,430.3 372.1 4,100.0 610.8 5,091.6 Over 10 years 19,790.7 678.1 8,524.4 1,942.6 10,001.8 37,750.4 1,179.3 15,450.9 2,739.9 20,738.9 Mortgage/Asset-Backed Securities 658.0 10.1 267.1 24.0 377.0 Total Fixed Maturity Securities $ 38,408.4 $ 1,189.4 $ 15,718.0 $ 2,763.9 $ 21,115.9 1 Allowance for Credit Losses The following chart depicts an analysis of our fixed maturity security portfolio between investment-grade and below-investment-grade categories as of September 30, 2024: Gross Unrealized Loss Fair Value Gross Unrealized Gain Amount Percent of Total Gross Unrealized Loss (in millions of dollars) Investment-Grade $ 36,287.2 $ 1,308.2 $ 2,308.8 97.2 % Below-Investment-Grade 1,496.3 30.0 65.6 2.8 Total Fixed Maturity Securities $ 37,783.5 $ 1,338.2 $ 2,374.4 100.0 % The unrealized losses on investment-grade fixed maturity securities principally relate to changes in interest rates or changes in market or sector credit spreads which occurred subsequent to the acquisition of the securities. Below-investment-grade fixed maturity securities are generally more likely to develop credit concerns than investment-grade securities. At September 30, 2024, the unrealized losses in our below-investment-grade fixed maturity securities were generally due to credit spreads in certain industries or sectors and, to a lesser extent, credit concerns related to specific securities. For each specific security in an unrealized loss position, we believe that there are positive factors which mitigate credit concerns and that the securities for which we have not recorded a credit loss will recover in value. We have the ability and intent to continue to hold these securities to recovery of amortized cost less allowance for credit losses. As of September 30, 2024, we held 835 individual investment-grade fixed maturity securities and 58 individual below-investment-grade fixed maturity securities that were in an unrealized loss position, of which 795 investment-grade fixed maturity securities and 50 below-investment-grade fixed maturity securities had been in an unrealized loss position continuously for over one year. In determining when a decline in fair value below amortized cost of a fixed maturity security represents a credit loss, we evaluate the following factors: • Whether we expect to recover the entire amortized cost basis of the security • Whether we intend to sell the security or will be required to sell the security before the recovery of its amortized cost basis • Whether the security is current as to principal and interest payments • The significance of the decline in value • Current and future business prospects and trends of earnings • The valuation of the security's underlying collateral • Relevant industry conditions and trends relative to their historical cycles • Market conditions • Rating agency and governmental actions • Bid and offering prices and the level of trading activity • Adverse changes in estimated cash flows for securitized investments • Changes in fair value subsequent to the balance sheet date • Any other key measures for the related security While determining whether a credit loss exists is a judgmental area, we utilize a formal, well-defined, and disciplined process to monitor and evaluate our fixed income investment portfolio, supported by issuer specific research and documentation as of the end of each period. The process results in a thorough evaluation of investments and the recording of credit losses on a timely basis for investments determined to have a credit loss. We calculate the allowance for credit losses of fixed maturity securities based on the present value of our best estimate of cash flows expected to be collected, discounted using the effective interest rate implicit in the security at the date of acquisition. When estimating future cash flows, we analyze the strength of the issuer’s balance sheet, its debt obligations and near-term funding arrangements, cash flow and liquidity, the profitability of its core businesses, the availability of marketable assets which could be sold to increase liquidity, its industry fundamentals and regulatory environment, and its access to capital markets. The following tables present a rollforward of the allowance for credit losses on available-for-sale fixed maturity securities, which were classified as "all other corporate bonds" during the three and nine months ended September 30, 2024. Three Months Ended September 30 2024 2023 (in millions of dollars) Balance, beginning of period $ 5.1 $ — Change in allowance on securities with allowance recorded in previous period 0.2 — Change in allowance on securities sold during the period (2.4) — Balance, end of period $ 2.9 $ — Nine Months Ended September 30 2024 2023 (in millions of dollars) Balance, beginning of period $ 2.2 $ — Credit losses on securities for which credit losses were not previously recorded 2.9 — Change in allowance on securities with allowance recorded in previous period 0.2 — Change in allowance on securities sold during the period (2.4) — Balance, end of period $ 2.9 $ — At September 30, 2024, we had commitments of $38.0 million to fund private placement fixed maturity securities, the amount of which may or may not be funded. Variable Interest Entities We invest in variable interests issued by variable interest entities. These investments, which are passive in nature, include minority ownership interests in private equity partnerships, tax credit partnerships, and special purpose entities. Our maximum exposure to loss is limited to the carrying value of these investments in private equity partnerships, tax credit partnerships, and special purpose entities. For those variable interests that are not consolidated in our financial statements, we are not the primary beneficiary because we have neither the power to direct the activities that are most significant to economic performance nor the responsibility to absorb a majority of the expected losses. The determination of whether we are the primary beneficiary is performed at the time of our initial investment and at the date of each subsequent reporting period. As of September 30, 2024, the carrying amount of our variable interest entity investments that are not consolidated in our financial statements was $1,428.3 million, comprised of $0.3 million of tax credit partnerships and $1,428.0 million of private equity partnerships. At December 31, 2023, the carrying amount of our variable interest entity investments that are not consolidated in our financial statements was $1,326.5 million, comprised of $0.3 million of tax credit partnerships and $1,326.2 million of private equity partnerships. These variable interest entity investments are reported as other long-term investments in our consolidated balance sheets. Mortgage Loans Our mortgage loan portfolio is well diversified by both geographic region and property type to reduce risk of concentration. All of our mortgage loans are collateralized by commercial real estate. When issuing a new loan, our general policy is not to exceed a loan-to-value ratio, or the ratio of the loan balance to the estimated fair value of the underlying collateral, of 75 percent. We update the loan-to-value ratios based on internal valuation of the collateral at least every three years for each loan, and properties undergo a general inspection at least every two years. Our general policy for newly issued loans is to have a debt service coverage ratio greater than 1.25 times on a normalized 25 year amortization period. We update our debt service coverage ratios annually. We carry our mortgage loans at amortized cost less an allowance for expected credit losses. The amortized cost of our mortgage loans was $2,255.4 million and $2,328.4 million at September 30, 2024 and December 31, 2023, respectively. The allowance for expected credit losses was $16.5 million and $10.2 million at September 30, 2024 and December 31, 2023, respectively. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. We report accrued interest income for our mortgage loans as accrued investment income on our consolidated balance sheets, and the amount of the accrued income was $7.0 million and $7.2 million at September 30, 2024 and December 31, 2023, respectively. The carrying amount of mortgage loans by property type and geographic region are presented below. September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Amount Percent of Total Carrying Amount Percent of Total Property Type Apartment $ 662.9 29.6 % $ 685.8 29.6 % Industrial 684.2 30.6 706.0 30.5 Office 354.1 15.8 379.9 16.4 Retail 496.1 22.1 503.9 21.7 Other 41.6 1.9 42.6 1.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % Region New England $ 53.2 2.4 % $ 55.1 2.4 % Mid-Atlantic 162.4 7.3 155.1 6.7 East North Central 294.0 13.1 314.4 13.6 West North Central 158.9 7.1 163.5 7.0 South Atlantic 537.1 24.0 553.0 23.8 East South Central 107.8 4.8 110.7 4.8 West South Central 195.5 8.7 200.9 8.7 Mountain 269.5 12.0 282.7 12.2 Pacific 460.5 20.6 482.8 20.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % The risk in our mortgage loan portfolio is primarily related to vacancy rates. Events or developments, such as economic conditions that impact the ability of the borrowers to ensure occupancy of the property, may have a negative effect on our mortgage loan portfolio, particularly to the extent that our portfolio is concentrated in an affected region or property type. An increase in vacancies increases the probability of default, which would negatively affect our expected losses in our mortgage loan portfolio. We evaluate each of our mortgage loans individually for impairment and assign an internal quality rating based on a comprehensive rating system used to evaluate the risk of the loan. The factors we use to derive our internal quality ratings may include the following: • Loan-to-value ratio based on internal valuation of the property • Debt service coverage ratio based on current operating income • Property location, including regional economics, trends, and demographics • Age, condition, and construction quality of property • Current and historical occupancy of property • Lease terms relative to market • Tenant size and financial strength • Borrower's financial strength • Borrower's equity in transaction • Additional collateral, if any Although all available and applicable factors are considered in our analysis, loan-to-value and debt service coverage ratios are the most critical factors in determining whether we will initially issue the loan and also in assigning values and determining impairment. We assign an overall rating to each loan using an internal rating scale of AA (highest quality) to B (lowest quality). We review and adjust, as needed, our internal quality ratings on an annual basis. This review process is performed more frequently for mortgage loans deemed to have a higher risk of delinquency. We estimate an allowance for credit losses that we expect to incur over the life of our mortgage loans using a probability of default method. For each loan, we estimate the probability that the loan will default before its maturity (probability of default) and the amount of the loss if the loan defaults (loss given default). These two factors result in an expected loss percentage that is applied to the amortized cost of each loan to determine the expected credit loss. As we are the original underwriter of the mortgage loans, the amortized cost generally equals the principal amount of the loan. We measure losses on defaults of our mortgage loans as the excess amortized cost of the mortgage loan over the fair value of the underlying collateral in the event that we foreclose on the loan or over the expected future cash flows of the loan if we retain the mortgage loan until payoff. We do not purchase mortgage loans with existing credit impairments. In estimating the probability of default, we consider historical experience, current market conditions, and reasonable and supportable forecasts about the future market conditions. We utilize our historical loan experience in combination with a large third-party industry database for a period of time that aligns with the average life of our loans based on the maturity dates of the loans and prepayment experience. Our model utilizes an industry database of the historical loss experience based on our actual portfolio characteristics such as loan-to-value, debt service coverage, collateral type, geography, and late payment history. In addition, because we actively manage our portfolio, we may extend the term of a loan in certain situations and will accordingly extend the maturity date in the estimate of probability of default. In estimating the loss given default, we primarily consider the type and value of collateral and secondarily the expected liquidation costs and time to recovery. The primary market factors that we consider in our forecast of future market conditions are gross domestic product, unemployment rates, interest rates, inflation, commercial real estate values, household formation, and retail sales. We also forecast certain loan specific factors such as growth in the fair value and net operating income of collateral by property type. We include our estimate of these factors over a two-year period and for the remainder of the loans’ estimated lives, adjusted for estimated prepayments. Past the two-year forecast period, we revert to the historical assumptions ratably by the end of the fifth year of the loan after which we utilize only historical assumptions. We utilize various scenarios to estimate our allowance for expected losses ranging from a base case scenario that reflects normal market conditions to a severe case scenario that reflects adverse market conditions. We will adjust our allowance each period to utilize the scenario or weighting of the scenarios that best reflects our view of current market conditions. The following tables present information about mortgage loans by the applicable internal quality indicators: September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Amount Percent of Total Carrying Amount Percent of Total Internal Mortgage Rating AA $ 94.5 4.2 % $ 85.2 3.7 % A 982.2 43.9 942.5 40.6 BBB 1,064.4 47.5 1,249.5 53.9 BB 97.8 4.4 41.0 1.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % Loan-to-Value Ratio 1 <= 65% $ 1,527.0 68.2 % $ 1,409.9 60.8 % > 65% <= 75% 481.6 21.5 707.0 30.5 > 75% <= 85% 148.5 6.6 136.5 5.9 > 85% 81.8 3.7 64.8 2.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property There were no gross write-offs for the periods ending September 30, 2024 or December 31, 2023. The following tables present the amortized cost of our mortgage loans by year of origination and internal quality indicators at September 30, 2024 and December 31, 2023, respectively: September 30, 2024 Prior to 2020 2020 2021 2022 2023 2024 Total (in millions of dollars) Internal Mortgage Rating AA $ 88.1 $ — $ 6.4 $ — $ — $ — $ 94.5 A 684.4 92.6 145.0 24.3 38.0 — 984.3 BBB 710.4 63.1 181.1 63.8 29.0 23.1 1,070.5 BB 106.1 — — — — — 106.1 Total Amortized Cost 1,589.0 155.7 332.5 88.1 67.0 23.1 2,255.4 Allowance for credit losses (14.1) (0.5) (1.1) (0.3) (0.4) (0.1) (16.5) Carrying Amount $ 1,574.9 $ 155.2 $ 331.4 $ 87.8 $ 66.6 $ 23.0 $ 2,238.9 Loan-to-Value Ratio 1 <=65% $ 1,174.1 $ 113.7 $ 188.8 $ 15.6 $ 38.7 $ — $ 1,530.9 >65<=75% 231.2 33.9 94.9 72.5 28.3 23.1 483.9 >75%<=85% 122.6 8.1 20.3 — — — 151.0 >85% 61.1 — 28.5 — — — 89.6 Total Amortized Cost 1,589.0 155.7 332.5 88.1 67.0 23.1 2,255.4 Allowance for credit losses (14.1) (0.5) (1.1) (0.3) (0.4) (0.1) (16.5) Carrying Amount $ 1,574.9 $ 155.2 $ 331.4 $ 87.8 $ 66.6 $ 23.0 $ 2,238.9 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property December 31, 2023 Prior to 2019 2019 2020 2021 2022 2023 Total (in millions of dollars) Internal Mortgage Rating AA $ 74.3 $ 11.0 $ — $ — $ — $ — $ 85.3 A 589.0 100.3 94.1 100.1 23.2 38.0 944.7 BBB 618.4 224.8 71.4 248.0 64.4 29.2 1,256.2 BB 42.2 — — — — — 42.2 Total Amortized Cost 1,323.9 336.1 165.5 348.1 87.6 67.2 2,328.4 Allowance for credit losses (6.3) (1.3) (0.6) (1.0) (0.6) (0.4) (10.2) Carrying Amount $ 1,317.6 $ 334.8 $ 164.9 $ 347.1 $ 87.0 $ 66.8 $ 2,318.2 Loan-to-Value Ratio 1 <=65% $ 908.3 $ 197.7 $ 116.4 $ 145.2 $ 16.2 $ 30.0 $ 1,413.8 >65<=75% 252.1 138.4 40.8 171.0 71.4 37.2 710.9 >75%<=85% 97.3 — 8.3 31.9 — — 137.5 >85% 66.2 — — — — — 66.2 Total Amortized Cost 1,323.9 336.1 165.5 348.1 87.6 67.2 2,328.4 Allowance for credit losses (6.3) (1.3) (0.6) (1.0) (0.6) (0.4) (10.2) Carrying Amount $ 1,317.6 $ 334.8 $ 164.9 $ 347.1 $ 87.0 $ 66.8 $ 2,318.2 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property The following tables present a roll-forward of the allowance for expected credit losses by loan-to-value ratio for the three and nine months ended September 30, 2024 and 2023 : Three Months Ended September 30, 2024 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.7 $ 0.3 $ — $ — $ 4.0 >65<=75% 3.3 (1.1) — — 2.2 >75%<=85% 1.7 0.8 — — 2.5 >85% 3.4 4.4 — — 7.8 Total $ 12.1 $ 4.4 $ — $ — $ 16.5 Three Months Ended September 30, 2023 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.3 $ (0.1) $ — $ — $ 3.2 >65<=75% 4.8 (0.4) — — 4.4 >75%<=85% 0.9 — — — 0.9 >85% 2.1 (0.4) — — 1.7 Total $ 11.1 $ (0.9) $ — $ — $ 10.2 Nine Months Ended September 30, 2024 Beginning of Year Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.8 $ 0.2 $ — $ — $ 4.0 >65<=75% 3.8 (1.6) — — 2.2 >75%<=85% 1.2 1.3 — — 2.5 >85% 1.4 6.4 — — 7.8 Total $ 10.2 $ 6.3 $ — $ — $ 16.5 Nine Months Ended September 30, 2023 Beginning of Year Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.0 $ 0.2 $ — $ — $ 3.2 >65<=75% 4.7 (0.3) — — 4.4 >75%<=85% 1.1 (0.2) — — 0.9 >85% 0.5 1.2 — — 1.7 Total $ 9.3 $ 0.9 $ — $ — $ 10.2 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property During the three and nine months ended September 30, 2024, all commercial mortgage loans which were previously modified for borrowers experiencing financial difficulties were current. During the three and nine months ended September 30, 2023, we granted an other-than-insignificant payment delay for a commercial mortgage loan with an amortized cost of $14.2 million, which deferred the principal payment for 18 months. This modification represented less than one percent of the commercial mortgage loan portfolio balance. There were no troubled debt restructurings for the three and nine months ended September 30, 2024. At September 30, 2024 and December 31, 2023, we held no mortgage loans that were greater than 90 days past due regarding principal and/or interest payments. As of September 30, 2024 and December 31, 2023, we had no loan foreclosures. Other than our allowance for expected credit losses, we had no specifically identified impaired mortgage loans during the three and nine months ended September 30, 2024 or 2023, nor did we recognize any interest income on mortgage loans subsequent to impairment. At September 30, 2024, we had $28.5 million commitments to fund commercial mortgage loans. Consistent with how we determine the estimate of current expected credit losses for our funded mortgage loans each period, we estimate expected credit losses for loans that hav e not been funded but we are committed to fund at the end of each period. At September 30, 2024, we had $0.1 million of expected credit losses related to unfunded commitments on our consolidated balance sheets. At December 31, 2023, we had no expected credit losses related to unfunded commitments on our consolidated balance sheets. Investment Real Estate Our real estate held for the production of income balance was $60.8 million and $64.4 million at September 30, 2024 and December 31, 2023, respectively, and the associated accumulated depreciation was $130.8 million and $127.2 million at September 30, 2024 and December 31, 2023, respectively. We did not recognize any impairments related to our real estate during the three and nine months ended September 30, 2024. For the three and nine months ended September 30, 2023, we recognized a $3.0 million impairment related to certain of our real estate held for investment. Our held for sale real estate balance was $40.9 million at both September 30, 2024 and December 31, 2023 and the associated accumulated depreciation was $54.2 million at both September 30, 2024 and December 31, 2023. The estimated fair values less costs to sell are above the carrying values of the properties and we expect to close the sales of the properties within the next twelve months. Transfers of Financial Assets To manage our cash position more efficiently, we may enter into repurchase agreements with unaffiliated financial institutions. We generally use repurchase agreements as a means to finance the purchase of invested assets or for short-term general business purposes until projected cash flows become available from our operations or existing investments. Our repurchase agreements are typically outstanding for less than 30 days. We post collateral through our repurchase agreement transactions whereby the counterparty commits to purchase securities with the agreement to resell them to us at a later, specified date. The fair value of collateral posted is generally 102 percent of the cash received. Our investment policy also permits us to lend fixed maturity securities to unaffiliated financial institutions in short-term securities lending agreements. These agreements increase our investment income with minimal risk. Our securities lending policy requires that a minimum of 102 percent of the fair value of the securities loaned be maintained as collateral. We may receive cash and/or securities as collateral under these agreements. Cash received as collateral is typically reinvested in short-term investments. If securities are received as collateral, we are not permitted to sell or re-post them. As of September 30, 2024, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $57.9 million, for which we received collateral in the form of cash and securities of $25.8 million and $34.4 million, respectively. As of December 31, 2023, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $72.0 million, for which we received collateral in the form of cash and securities of $63.1 million and $12.5 million, respectively. We had no outstanding repurchase agreements at September 30, 2024 or December 31, 2023. The remaining contractual maturities of our securities lending agreements disaggregated by class of collateral pledged are as follows: September 30, 2024 December 31, 2023 Overnight and Continuous (in millions of dollars) Borrowings Public Utilities $ 3.7 $ 1.8 All Other Corporate Bonds 22.1 61.3 Total Borrowings 25.8 63.1 Gross Amount of Recognized Liability for Securities Lending Transactions 25.8 63.1 Amounts Related to Agreements Not Included in Offsetting Disclosure Contained Herein $ — $ — Certain of our U.S. insurance subsidiaries are members of regional FHLBs. Membership, which requires that we purchase a minimum amount of FHLB common stock on which we receive dividends, provides access to low-cost funding. Advances received from the FHLB are used for the purchase of fixed maturity securities. Additional common stock purchases may be required, based on the amount of funds we borrow from the FHLBs. The carrying value of common stock owned, collateral posted, and advances received are as follows: September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Value of FHLB Common Stock $ 25.6 $ 15.7 Advances from FHLB 299.0 64.5 Carrying Value of Collateral Posted to FHLB Fixed Maturity Securities $ 600.7 $ 589.0 Commercial Mortgage Loans 940.6 986.8 Total Carrying Value of Collateral Posted to FHLB $ 1,541.3 $ 1,575.8 Offsetting of Financial Instruments We enter into master netting agreements with each of our derivative's counterparties. These agreements provide for conditional rights of set-off upon the occurrence of an early termination event. An early termination event is considered a default, and it allows the non-defaulting party to offset its contracts in a loss position against any gain positions or payments due to the defaulting party. Under our agreements, default type events are defined as failure to pay or deliver as contractually agreed, misrepresentation, bankruptcy, or merger without assumption. See Note 5 for further discussion of collateral related to our derivative contracts. We have securities lending agreements with unaffiliated financial institutions that post collateral to us in return for the use of our fixed maturity securities. A right of set-off exists that allows us to keep and apply collateral received in the event of default by the counterparty. Default within a securities lending agreement would typically occur if the counterparty failed to return the securities borrowed from us as contractually agreed. In addition, if we default by not returning collateral received, the counterparty has a right of set-off against our securities or any other amounts due to us. Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties. September 30, 2024 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 105.5 $ — $ 105.5 $ (102.9) $ (2.3) $ 0.3 Securities Lending 57.9 — 57.9 (32.1) (25.8) — Total $ 163.4 $ — $ 163.4 $ (135.0) $ (28.1) $ 0.3 Financial Liabilities: Derivatives $ 130.2 $ — $ 130.2 $ (127.7) $ — $ 2.5 Securities Lending 25.8 — 25.8 (25.8) — — Total $ 156.0 $ — $ 156.0 $ (153.5) $ — $ 2.5 December 31, 2023 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 99.9 $ — $ 99.9 $ (91.9) $ (6.4) $ 1.6 Securities Lending 72.0 — 72.0 (8.9) (63.1) — Total $ 171.9 $ — $ 171.9 $ (100.8) $ (69.5) $ 1.6 Financial Liabilities: Derivatives $ 116.2 $ — $ 116.2 $ (109.4) $ — $ 6.8 Securities Lending 63.1 — 63.1 (63.1) — — Total $ 179.3 $ — $ 179.3 $ (172.5) $ — $ 6.8 Net Investment Income Net investment income reported in our consolidated statements of income is presented below. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Fixed Maturity Securities $ 465.4 $ 457.9 $ 1,388.5 $ 1,383.7 Derivatives 8.1 11.6 25.0 34.5 Mortgage Loans 22.0 22.9 66.6 69.8 Policy Loans 5.7 5.4 16.3 15.6 Other Long-term Investments Perpetual Preferred Securities 1 — 0.4 0.3 2.2 Private Equity Partnerships 2 19.6 22.6 72.6 56.7 Other 3.4 2.6 8.5 7.1 Short-term Investments 24.0 19.1 65.7 49.4 Gross Investment Income 548.2 542.5 1,643.5 1,619.0 Less Investment Expenses 17.5 13.5 48.3 44.0 Less Investment Income on Participation Fund Account Assets 2.9 3.0 8.8 9.1 Net Investment Income $ 527.8 $ 526.0 $ 1,586.4 $ 1,565.9 1 The net unrealized gain (loss) recognized in net investment income for the three months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was $0.2 million. The net unrealized gain (loss) recognized in net investment income for the nine months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was de minimis. The net unrealized gain (loss) recognized in net investment income for the three and nine months ended September 30, 2023 related to perpetual preferred securities still held at September 30, 2023 was $(0.4) million and $0.1 million, respectively. 2 The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2024 related to private equity partnerships

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Note 5 - Derivative Financial Instruments Purpose of Derivatives We are exposed to certain risks relating to our ongoing business operations. The primary risks managed by using derivative instruments are interest rate risk, risk related to matching duration for our assets and liabilities, foreign currency risk, and equity risk. Historically, we have utilized current and forward interest rate swaps, current and forward currency swaps, forward benchmark interest rate locks, currency forward contracts, forward contracts on specific fixed income securities, and total return swaps. Transactions hedging interest rate risk are primarily associated with our individual and group long-term care and individual and group disability products. All other product portfolios are periodically reviewed to determine if hedging strategies would be appropriate for risk management purposes. We do not use derivative financial instruments for speculative purposes. Derivatives designated as cash flow hedges and used to reduce our exposure to interest rate and duration risk are as follows: • Interest rate swaps were used to hedge interest rate risks and to improve the matching of assets and liabilities. An interest rate swap is an agreement in which we agree with other parties to exchange, at specified intervals, the difference between fixed rate and variable rate interest amounts. We used interest rate swaps to hedge the anticipated purchase of fixed maturity securities thereby protecting us from the potential adverse impact of declining interest rates on the associated policy reserves. We also used interest rate swaps to hedge the potential adverse impact of rising interest rates in anticipation of issuing fixed rate long-term debt. • Forward benchmark interest rate locks are used to minimize interest rate risk associated with the anticipated purchase or associated future coupons of fixed maturity securities or the anticipated issuance of fixed rate long-term debt. A forward benchmark interest rate lock is a derivative contract without an initial investment where we and the counterparty agree to purchase or sell a specific benchmark interest rate fixed maturity bond at a future date at a predetermined price or yield. Derivatives designated as either cash flow or fair value hedges and used to reduce our exposure to foreign currency risk are as follows: • Foreign currency interest rate swaps are used to hedge the currency risk of certain foreign currency-denominated fixed maturity securities owned for portfolio diversification. Under these swap agreements, we agree to pay, at specified intervals, fixed rate foreign currency-denominated principal and interest payments in exchange for fixed rate payments in the functional currency of the operating segment. Derivatives not designated as hedging instruments and used to reduce our exposure to foreign currency risk and volatility of the underlying deferred assets in our non-qualified defined contribution plan are as follows: • Foreign currency interest rate swaps previously designated as hedges were used to hedge the currency risk of certain foreign currency-denominated fixed maturity securities owned for portfolio diversification. These derivatives were effective hedges prior to novation to a new counterparty. In conjunction with the novation, these derivatives were de-designated as hedges. We agree to pay, at specified intervals, fixed rate foreign currency-denominated principal and interest payments in exchange for fixed rate payments in the functional currency of the operating segment. We hold offsetting swaps wherein we agree to pay fixed rate principal and interest payments in the functional currency of the operating segment in exchange for fixed rate foreign currency-denominated payments. • Foreign currency forward contracts are used to minimize foreign currency risk. A foreign currency forward is a derivative without an initial investment where we and the counterparty agree to exchange a specific amount of currencies, at a specific exchange rate, on a specific date. We use these forward contracts to hedge the currency risk arising from foreign-currency denominated investments. • Total Return Swap s are used to economically hedge a portion of the liability related to our non-qualified defined contribution plan. A total return swap is an agreement in which we pay a floating rate of interest to the counterparty and receive the total return on a portfolio of mutual funds and exchange traded funds. These swaps are cash settled on the last day of every month and the notional is re-established each month based on plan participant actions. Derivative Risks The basic types of risks associated with derivatives are market risk (that the value of the derivative will be adversely impacted by changes in the market, primarily changes in interest rates, exchange rates, and equity prices) and credit risk (that the counterparty will not perform according to the terms of the contract). The market risk of the derivatives should generally offset the market risk associated with the hedged financial instrument or liability. To help limit the credit exposure of the derivatives, we enter into master netting agreements with our counterparties whereby contracts in a gain position can be offset against contracts in a loss position. We also typically enter into bilateral, cross-collateralization agreements with our counterparties to help limit the credit exposure of the derivatives. These agreements require the counterparty in a loss position to submit acceptable collateral with the other counterparty in the event the net loss position meets or exceeds an agreed upon amount. Credit exposure on derivatives is limited to the value of those contracts in a net gain position, including accrued interest receivable less collateral held. At September 30, 2024 and December 31, 2023, we had $0.3 million and $1.6 million credit exposure on derivatives, respectively. The table below summarizes the nature and amount of collateral received from and posted to our derivative counterparties. September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Value of Collateral Received from Counterparties Cash $ 3.4 $ 11.1 Fixed Maturity Securities 30.9 26.3 $ 34.3 $ 37.4 Carrying Value of Collateral Posted to Counterparties Cash $ — $ — Fixed Maturity Securities 50.6 39.8 $ 50.6 $ 39.8 See Note 4 for further discussion of our master netting agreements. All of our derivative instruments contain provisions that require us to maintain specified issuer credit ratings and financial strength ratings. Should our ratings fall below these specified levels, we would be in violation of the provisions, and our derivatives counterparties could terminate our contracts and request immediate payment. The aggregate fair value of all derivative instruments with credit risk-related contingent features that were in a liability position was $130.2 million and $116.2 million at September 30, 2024 and December 31, 2023, respectively. Cash Flow Hedges As of September 30, 2024 and December 31, 2023, we had $142.5 million and $149.5 million, respectively, notional amount of receive fixed, pay fixed, open current and forward foreign currency interest rate swaps to hedge fixed income foreign currency-denominated securities. As of September 30, 2024 and December 31, 2023, we had $2,523.0 million and $1,905.0 million, respectively, notional amount of forward benchmark interest rate locks to hedge the anticipated purchase or associated future coupons of fixed maturity securities. As of September 30, 2024, we expect to amortize approximately $9.2 million of net deferred gains on derivative instruments during the next twelve months. This amount will be reclassified from AOCI into earnings and reported on the same income statement line item as the hedged item. The income statement line items that will be affected by this amortization are net investment income and interest and debt expense. Additional amounts that may be reclassified from AOCI into earnings to offset the earnings impact of foreign currency translation of hedged items are not estimable. As of September 30, 2024, we are hedging the variability of future cash flows associated with forecasted transactions through the year 2064. Fair Value Hedges As of September 30, 2024 and December 31, 2023, we had $693.2 million and $642.5 million, respectively, notional amount of receive fixed, pay fixed, open current and forward foreign currency interest rate swaps to hedge fixed income foreign currency-denominated securities. The following table summarizes the carrying amount of hedged assets and the related cumulative basis adjustments related to our fair value hedges: Carrying Amount of Hedged Assets Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets September 30, 2024 December 31, 2023 September 30, 2024 December 31, 2023 (in millions of dollars) Fixed maturity securities: Receive fixed functional currency interest, pay fixed foreign currency interest $ 592.9 $ 529.2 $ (0.5) $ (6.1) For the three and nine months ended September 30, 2024, $8.2 million and $9.5 million, respectively, of the derivative instruments' gain (loss) related to cross-currency basis spread and forward points was excluded from the assessment of hedge effectiveness. For the three and nine months ended September 30, 2023, $(19.4) million and $(26.6) million, respectively, of the derivative instruments' gain (loss) related to cross-currency basis spread and forward points was excluded from the assessment of hedge effectiveness. There were no instances wherein we discontinued fair value hedge accounting due to a hedged firm commitment no longer qualifying as a fair value hedge. Derivatives not Designated as Hedging Instruments As of September 30, 2024 and December 31, 2023, we held $125.9 million and $132.0 million, respectively, notional amount of receive fixed, pay fixed, foreign currency interest rate swaps. These derivatives are not designated as hedges, and as such, changes in fair value related to these derivatives are reported in earnings as a component of net investment gain or loss. As of September 30, 2024 and December 31, 2023, we held $54.6 million and $52.5 million, respectively, notional amount of foreign currency forwards to mitigate the foreign currency risk associated with specific securities owned. These derivatives are not designated as hedges, and as such, changes in fair value related to these derivatives are reported in earnings as a component of net investment gain or loss. As of September 30, 2024 and December 31, 2023, we held $126.3 million and $102.2 million, respectively, notional amount of total return swaps to mitigate the volatility associated with changes in the fair value of the underlying notional assets in our non-qualified defined contribution plan. This derivative is an economic hedge not designated as a hedging instrument, and changes in fair value are reported as a component of other expenses in our income statement. We have an embedded derivative in a modified coinsurance arrangement for which we include in our net investment gains and losses, a calculation intended to estimate the value of the option of our reinsurance counterparty to cancel the reinsurance contract with us. However, neither party can unilaterally terminate the reinsurance agreement except in extreme circumstances resulting from regulatory supervision, delinquency proceedings, or other direct regulatory action. Cash settlements or collateral related to this embedded derivative are not required at any time during the reinsurance contract or at termination of the reinsurance contract. There are no credit-related counterparty triggers, and any accumulated embedded derivative gain or loss reduces to zero over time as the reinsured business winds down. Locations and Amounts of Derivative Financial Instruments The following tables summarize the notional amounts and fair values of derivative financial instruments, as reported in our consolidated balance sheets. Derivative assets are included in other long-term investments, while derivative liabilities are included in other liabilities within our consolidated balance sheets. The notional amounts represent the basis upon which our counterparty pay and receive amounts are calculated. September 30, 2024 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Forward Benchmark Interest Rate Locks $ 2,523.0 $ 47.4 $ 94.7 Foreign Currency Interest Rate Swaps 142.5 14.9 3.0 Total Cash Flow Hedges 2,665.5 62.3 97.7 Fair Value Hedges Foreign Currency Interest Rate Swaps 693.2 41.1 15.7 Total Designated as Hedging Instruments $ 3,358.7 $ 103.4 $ 113.4 Not Designated as Hedging Instruments Foreign Currency Forwards $ 54.6 $ 2.1 $ 0.5 Foreign Currency Interest Rate Swaps 125.9 — 16.3 Total Return Swaps 126.3 — — Embedded Derivative in Modified Coinsurance Arrangement — 4.6 — Total Not Designated as Hedging Instruments $ 306.8 $ 6.7 $ 16.8 Total Derivatives $ 3,665.5 $ 110.1 $ 130.2 December 31, 2023 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Forward Benchmark Interest Rate Locks $ 1,905.0 $ 44.5 $ 77.8 Foreign Currency Interest Rate Swaps 149.5 14.2 4.5 Total Cash Flow Hedges 2,054.5 58.7 82.3 Fair Value Hedges Foreign Currency Interest Rate Swaps 642.5 38.2 16.7 Total Designated as Hedging Instruments $ 2,697.0 $ 96.9 $ 99.0 Not Designated as Hedging Instruments Foreign Currency Forwards $ 52.5 $ 3.0 $ 0.2 Foreign Currency Interest Rate Swaps 132.0 — 17.0 Total Return Swaps 102.2 — — Embedded Derivative in Modified Coinsurance Arrangement — — 1.5 Total Not Designated as Hedging Instruments $ 286.7 $ 3.0 $ 18.7 Total Derivatives $ 2,983.7 $ 99.9 $ 117.7 The following tables summarize the location of gains and losses of derivative financial instruments designated as hedging instruments, as reported in our consolidated statements of income. Three Months Ended September 30 2024 2023 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 527.8 $ (12.9) $ 49.2 $ 526.0 $ (31.0) $ 48.6 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged Items 21.1 — 0.7 49.7 — 0.7 Derivatives Designated as Hedging Instruments 3.7 — — 8.3 — — Foreign Exchange Contracts: Hedged Items 2.3 (0.7) — 2.3 (0.1) — Derivatives Designated as Hedging Instruments 0.9 0.7 — 0.4 — — Forward Benchmark Interest Rate Locks: Hedged Items 10.7 — — 3.9 — — Derivatives Designated as Hedging Instruments (0.3) — — (0.1) — — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged Items 4.9 25.2 — 3.9 (15.2) — Derivatives Designated as Hedging Instruments 4.2 (25.2) — 3.1 15.2 — Nine Months Ended September 30 2024 2023 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 1,586.4 $ (24.5) $ 148.6 $ 1,565.9 $ (30.0) $ 145.6 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged Items 91.3 — 2.2 148.2 0.8 2.2 Derivatives Designated as Hedging Instruments 14.5 — — 27.7 — — Foreign Exchange Contracts: Hedged Items 6.5 (0.4) — 7.3 (0.1) — Derivatives Designated as Hedging Instruments 0.5 0.5 — 0.6 0.1 — Forward Benchmark Interest Rate Locks: Hedged Items 29.6 — — 7.7 — — Derivatives Designated as Hedging Instruments (0.7) — — (0.1) — — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged Items 13.4 5.6 — 10.3 (8.7) — Derivatives Designated as Hedging Instruments 11.5 (5.6) — 6.7 8.7 — The following table summarizes the location of gains and losses of derivative financial instruments designated as cash flow hedging instruments, as reported in our consolidated statements of comprehensive income (loss). Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Gain (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives Forwards $ 66.0 $ (158.9) $ (39.6) $ (159.7) Foreign Exchange Contracts (1.2) 3.4 2.6 0.7 Total $ 64.8 $ (155.5) $ (37.0) $ (159.0) The following table summarizes the location of gains and losses on our derivatives not designated as hedging instruments, as reported in our consolidated statements of income. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Net Investment Gain (Loss) Foreign Exchange Contracts $ (2.2) $ 2.0 $ (0.2) $ 2.0 Embedded Derivative in Modified Coinsurance Arrangement (0.8) 9.2 6.1 14.7 Total $ (3.0) $ 11.2 $ 5.9 $ 16.7 Other Expenses (Gain) Loss on Total Return Swaps $ (5.4) $ 4.1 $ (14.1) $ (4.7)

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Components of our accumulated other comprehensive loss, after tax, and related changes are as follows: Net Unrealized Loss on Securities Effect of Change in Discount Rate Assumptions on the LFPB 1 Net Loss on Derivatives Foreign Currency Translation Adjustment Unrecognized Pension and Postretirement Benefit Costs Total (in millions of dollars) Balance at June 30, 2024 $ (2,723.8) $ 712.3 $ (164.6) $ (328.4) $ (341.7) $ (2,846.2) Other Comprehensive Income (Loss) Before Reclassifications 1,225.8 (1,239.3) 58.8 68.5 (4.2) 109.6 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 6.8 — (3.1) — 3.2 6.9 Net Other Comprehensive Income (Loss) 1,232.6 (1,239.3) 55.7 68.5 (1.0) 116.5 Balance at September 30, 2024 $ (1,491.2) $ (527.0) $ (108.9) $ (259.9) $ (342.7) $ (2,729.7) Balance at June 30, 2023 $ (2,762.6) $ 0.1 $ (33.3) $ (327.1) $ (334.7) $ (3,457.6) Other Comprehensive Income (Loss) Before Reclassifications (1,215.1) 1,688.4 (137.9) (55.1) 2.5 282.8 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 29.3 — (6.5) — 1.4 24.2 Net Other Comprehensive Income (Loss) (1,185.8) 1,688.4 (144.4) (55.1) 3.9 307.0 Balance at September 30, 2023 $ (3,948.4) $ 1,688.5 $ (177.7) $ (382.2) $ (330.8) $ (3,150.6) Balance at December 31, 2023 $ (1,919.1) $ (648.4) $ (73.7) $ (321.1) $ (345.7) $ (3,308.0) Other Comprehensive Income (Loss) Before Reclassifications 401.1 121.4 (24.3) 61.2 (6.6) 552.8 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 26.8 — (10.9) — 9.6 25.5 Net Other Comprehensive Income (Loss) 427.9 121.4 (35.2) 61.2 3.0 578.3 Balance at September 30, 2024 $ (1,491.2) $ (527.0) $ (108.9) $ (259.9) $ (342.7) $ (2,729.7) Balance at December 31, 2022 $ (3,028.4) $ 313.9 $ (9.6) $ (390.1) $ (334.1) $ (3,448.3) Other Comprehensive Income (Loss) Before Reclassifications (957.2) 1,374.6 (146.4) 7.9 (0.9) 278.0 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 37.2 — (21.7) — 4.2 19.7 Net Other Comprehensive Income (Loss) (920.0) 1,374.6 (168.1) 7.9 3.3 297.7 Balance at September 30, 2023 $ (3,948.4) $ 1,688.5 $ (177.7) $ (382.2) $ (330.8) $ (3,150.6) 1 Liability for Future Policy Benefits Amounts reclassified from accumulated other comprehensive loss were recognized in our consolidated statements of income as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Net Unrealized Loss on Securities Net Investment Loss on Fixed Maturity Securities Net Loss on Sales $ (7.4) $ (37.0) $ (28.6) $ (47.0) Impairment Loss (1.3) — (2.5) — Change in Allowance for Credit Losses (0.2) — (3.1) — (8.9) (37.0) (34.2) (47.0) Income Tax Benefit (2.1) (7.7) (7.4) (9.8) Total $ (6.8) $ (29.3) $ (26.8) $ (37.2) Net Loss on Derivatives Net Investment Income Gain on Interest Rate Swaps and Forwards $ 3.4 $ 8.3 $ 13.8 $ 27.6 Loss on Foreign Currency Interest Rate Swaps — (0.1) (0.1) (0.2) Net Investment Gain Gain on Foreign Currency Interest Rate Swaps 0.6 — 0.1 0.1 4.0 8.2 13.8 27.5 Income Tax Expense 0.9 1.7 2.9 5.8 Total $ 3.1 $ 6.5 $ 10.9 $ 21.7 Unrecognized Pension and Postretirement Benefit Costs Other Expenses Amortization of Net Actuarial Loss $ (4.2) $ (1.8) $ (12.4) $ (5.4) Amortization of Prior Service Credit 0.1 — 0.2 0.1 (4.1) (1.8) (12.2) (5.3) Income Tax Benefit (0.9) (0.4) (2.6) (1.1) Total $ (3.2) $ (1.4) $ (9.6) $ (4.2)

Liability for Future Policy Ben

Liability for Future Policy Benefits, Policyholder's Account Balances, and Deferred Acquisition Costs	9 Months Ended
	Sep. 30, 2024
Insurance [Abstract]
Long-Duration Insurance Contracts Disclosure	Liabilities for future policy benefits represent the cost of claims that we estimate we will eventually pay to our policyholders which includes policy liabilities for claims not yet incurred and for claims that have been incurred or are estimated to have been incurred but not yet reported to us. Liabilities for future policy benefits also include the related expenses for our non interest-sensitive life and accident and health products. The liability for future policy benefits is calculated based on the present value of the estimated future policy benefits less the present value of estimated future net premiums collected. Net premiums represent the portion of the gross premium required to provide for all benefits and expenses, excluding acquisition costs or any costs that are required to be charged to expense as incurred. In calculating the liability for future policy benefits, our long-duration contracts are grouped into cohorts by product type and contract issue year. The calculation of the liability for future policy benefits involves numerous assumptions including assumptions related to discount rate, lapses, mortality, and morbidity. Cash flow assumptions are reviewed and updated, as needed, at least annually. Assumptions may be updated more frequently if necessary based on trending experience and future expectations. On a quarterly basis, cohort level cash flow measures are updated based on the emergence of actual experience. The initial, also referred to as the original, discount rate assumptions established for each cohort are used to determine interest accretion. After policy issuance or policy renewal, the discount rate assumptions are updated quarterly and used to update the liability at each reporting date to the current discount rate. The weighted average current discount rate was 4.8 percent at September 30, 2024 and December 31, 2023. The weighted average current discount rate was 5.6 percent at September 30, 2023 compared to 5.0 percent at December 31, 2022, with the increase due primarily to an increase in U.S. Treasury rates. During the third quarter of 2024, we completed our annual cash flow assumption review and updated certain of our assumptions used to develop the liability for future policy benefits which resulted in a net decrease to the liability. The decrease to the liability for future policy benefits was driven primarily by assumption updates in our Closed Block long-term care product line, Unum US group disability product line, Unum US individual disability product line, and the Colonial Life segment. The Closed Block long-term care assumption updates were primarily driven by an increase to expected premium rate increase approvals within our existing premium rate increase program, partially offset by lower than expected persistency on group policies. The Unum US group disability product line assumption updates were primarily related to claim resolution assumptions driven by favorable claim recovery trends, while the Unum US individual disability product line assumption updates were primarily driven by favorable claim incidence trends. The Colonial Life segment assumption updates were driven by improved claim cost assumptions. During the third quarter of 2023, we completed our annual cash flow assumption review and updated certain of our assumptions used to develop the liability for future policy benefits which resulted in a net increase to the liability. The increase to the liability for future policy benefits was driven primarily by assumption updates in our Closed Block long-term care product line, partially offset by assumption updates in the Unum US group disability product line and in the Colonial Life segment. The long-term care assumption updates were primarily driven by lower expectations for active policy lapse and mortality assumptions, partially offset by an increase to expected premium rate increase approvals within our existing premium rate increase program. The Unum US group disability product line assumption updates were primarily related to claim resolution assumptions driven by favorable claim recovery trends, while the Colonial Life segment assumption updates were driven by improved claim cost assumptions and increases in policyholder lapse rates. Actual variance from expected experience during the first nine months of 2024 and 2023 was due primarily to the Unum US group disability, Closed Block long-term care, and the Unum US group life and accidental death and dismemberment product lines. During the first nine months of 2024 and 2023, the variance in the Unum US group disability product line was primarily due to higher than expected claim resolutions driven by recoveries. During the first nine months of 2024 and 2023, the variance in the Closed Block long-term care product line was driven primarily by higher than expected claim incidence. Also impacting the variance for the first nine months of 2024 was lower than expected policy terminations, partially offset by higher than expected claim resolutions. During the first nine months of 2024 and 2023, the variance in the Unum US group life and accidental death and dismemberment product line was driven primarily by lower than expected new claim incidence. Also contributing to the comparison for the first nine months of 2024 was higher than expected claim resolutions driven by recoveries. The variance for the first nine months of 2023 is also impacted by our Unum US individual disability product line which was driven primarily by lower than expected new claim incidence. For the nine months ended September 30, 2024 and 2023, there were certain cohorts within the Colonial Life segment, related to our cancer and critical illness product line, and within the Closed Block segment, related to our long-term care product line, for which net premiums exceeded gross premiums. The cohorts for which net premiums exceeded the gross premiums within the Closed Block segment resulted in a $70.8 million increase to income before income tax for the nine months ended September 30, 2024 and resulted in a $215.5 million reduction to income before income tax for the nine months ended September 30, 2023. For the nine months ended September 30, 2024 and 2023, the cohorts for which net premiums exceeded the gross premiums within the Colonial Life segment had an immaterial impact to income before income tax. The impact to income for capped cohorts includes the impact of assumption updates. There were no other product lines with cohorts for which net premiums exceeded gross premiums for the nine months ended September 30, 2024 or 2023. The following table presents balances as well as the changes in the liability for future policy benefits for traditional long duration products. Consolidated September 30 2024 2023 (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 14,417.8 $ 12,426.2 Beginning balance at original discount rate 14,243.2 12,695.3 Effect of changes in cash flow assumptions 73.0 1,499.2 Effect of actual variances from expected experience (151.9) (121.8) Adjusted beginning of year balance 14,164.3 14,072.7 Issuances 856.7 861.2 Interest accretion 481.8 430.8 Net premiums collected (1,222.6) (1,164.9) Foreign currency 7.3 (0.1) Ending balance at original discount rate 14,287.5 14,199.7 Effect of change in discount rate assumptions 319.0 (709.0) Balance, end of period $ 14,606.5 $ 13,490.7 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 52,423.6 $ 48,929.4 Beginning balance at original discount rate 51,305.7 49,689.0 Effect of changes in cash flow assumptions (248.5) 1,702.0 Effect of actual variances from expected experience (355.6) (356.4) Adjusted beginning of year balance 50,701.6 51,034.6 Issuances 1 2,506.9 2,547.0 Interest accretion 1,707.3 1,670.3 Benefit payments (4,078.4) (4,106.1) Foreign currency 121.0 19.6 Ending balance at original discount rate 50,958.4 51,165.4 Effect of change in discount rate assumptions 1,204.1 (3,111.7) Balance, end of period $ 52,162.5 $ 48,053.7 Net liability for future policy benefits $ 37,556.0 $ 34,563.0 Other 2 1,655.7 1,703.3 Total liability for future policy benefits 39,211.7 36,266.3 Less: Reinsurance recoverable related to future policy benefits 7,455.9 7,449.0 Net liability for future policy benefits, after reinsurance recoverable $ 31,755.8 $ 28,817.3 1 Issuances include new policy issuances for most product lines. For our Unum US group disability, Unum US group life and AD&D and Closed Block - All Other product lines and certain of our Unum International product lines, this line represents new claim incurrals. 2 Other primarily relates to our Closed Block - All Other product line. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products presented in the rollforward activity above. Consolidated Nine Months Ended September 30 2024 2023 (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 7,568.4 $ 7,278.4 Interest accretion $ 1,225.5 $ 1,239.5 Consolidated September 30 2024 2023 (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 104,039.1 $ 105,306.1 Expected future gross premiums $ 39,394.1 $ 38,581.4 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 25,941.4 $ 25,435.2 Weighted average interest rate: Interest accretion rate 4.9 % 4.8 % Current discount rate 4.8 % 5.6 % Weighted average duration of the liability 11.5 years 11.5 years The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Unum US segment. September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ — $ — $ 1,134.7 $ 1,296.7 $ 2,431.4 Beginning balance at original discount rate — — 1,192.5 1,294.4 2,486.9 Effect of changes in cash flow assumptions — — 41.5 (100.2) (58.7) Effect of actual variances from expected experience — — (72.1) (5.3) (77.4) Adjusted beginning of year balance — — 1,161.9 1,188.9 2,350.8 Issuances 1 — — 295.0 119.2 414.2 Interest accretion — — 29.9 39.8 69.7 Net premiums collected — — (144.9) (138.7) (283.6) Ending balance at original discount rate — — 1,341.9 1,209.2 2,551.1 Effect of change in discount rate assumptions — — (41.7) 16.7 (25.0) Balance, end of period $ — $ — $ 1,300.2 $ 1,225.9 $ 2,526.1 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 5,147.4 $ 922.0 $ 2,334.5 $ 3,348.6 $ 11,752.5 Beginning balance at original discount rate 5,277.1 936.5 2,422.0 3,313.9 11,949.5 Effect of changes in cash flow assumptions (76.4) (17.0) 51.6 (155.4) (197.2) Effect of actual variances from expected experience (152.4) (49.7) (81.1) (18.9) (302.1) Adjusted beginning of year balance 5,048.3 869.8 2,392.5 3,139.6 11,450.2 Issuances 1 893.7 333.3 315.1 127.1 1,669.2 Interest accretion 121.7 14.3 73.2 113.3 322.5 Benefit payments (1,109.7) (357.8) (170.3) (207.2) (1,845.0) Ending balance at original discount rate 4,954.0 859.6 2,610.5 3,172.8 11,596.9 Effect of change in discount rate assumptions (43.4) (6.3) (91.7) 65.8 (75.6) Balance, end of period $ 4,910.6 $ 853.3 $ 2,518.8 $ 3,238.6 $ 11,521.3 Net liability for future policy benefits $ 4,910.6 $ 853.3 $ 1,218.6 $ 2,012.7 $ 8,995.2 Other 0.1 0.8 2.7 28.1 31.7 Total liability for future policy benefits 4,910.7 854.1 1,221.3 2,040.8 9,026.9 Less: Reinsurance recoverable related to future policy benefits 26.8 5.7 13.7 154.6 200.8 Net liability for future policy benefits, after reinsurance recoverable $ 4,883.9 $ 848.4 $ 1,207.6 $ 1,886.2 $ 8,826.1 1 Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals. September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ — $ — $ 868.2 $ 1,202.9 $ 2,071.1 Beginning balance at original discount rate — — 937.9 1,228.1 2,166.0 Effect of changes in cash flow assumptions — — 180.7 5.0 185.7 Effect of actual variances from expected experience — — (98.2) (13.6) (111.8) Adjusted beginning of year balance — — 1,020.4 1,219.5 2,239.9 Issuances 1 — — 258.6 164.0 422.6 Interest accretion — — 21.4 36.3 57.7 Net premiums collected — — (124.2) (131.7) (255.9) Ending balance at original discount rate — — 1,176.2 1,288.1 2,464.3 Effect of change in discount rate assumptions — — (119.4) (62.2) (181.6) Balance, end of period $ — $ — $ 1,056.8 $ 1,225.9 $ 2,282.7 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 5,533.3 $ 972.6 $ 1,999.5 $ 3,192.8 $ 11,698.2 Beginning balance at original discount rate 5,793.1 998.5 2,141.2 3,244.5 12,177.3 Effect of changes in cash flow assumptions (100.2) — 170.1 7.9 77.8 Effect of actual variances from expected experience (187.8) (28.2) (109.6) (42.3) (367.9) Adjusted beginning of year balance 5,505.1 970.3 2,201.7 3,210.1 11,887.2 Issuances 1 907.1 356.1 270.4 173.8 1,707.4 Interest accretion 137.6 15.8 64.3 123.2 340.9 Benefit payments (1,186.8) (402.1) (143.9) (203.5) (1,936.3) Ending balance at original discount rate 5,363.0 940.1 2,392.5 3,303.6 11,999.2 Effect of change in discount rate assumptions (310.1) (35.6) (280.7) (190.0) (816.4) Balance, end of period $ 5,052.9 $ 904.5 $ 2,111.8 $ 3,113.6 $ 11,182.8 Net liability for future policy benefits $ 5,052.9 $ 904.5 $ 1,055.0 $ 1,887.7 $ 8,900.1 Other 0.5 1.0 2.4 26.0 29.9 Total liability for future policy benefits 5,053.4 905.5 1,057.4 1,913.7 8,930.0 Less: Reinsurance recoverable related to future policy benefits 32.8 6.2 13.2 148.1 200.3 Net liability for future policy benefits, after reinsurance recoverable $ 5,020.6 $ 899.3 $ 1,044.2 $ 1,765.6 $ 8,729.7 1 Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Unum US segment presented in the rollforward activity above. Nine Months Ended September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 2,294.8 $ 1,496.3 $ 621.3 $ 494.2 $ 4,906.6 Interest accretion $ 121.7 $ 14.3 $ 43.3 $ 73.5 $ 252.8 Nine Months Ended September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 2,210.4 $ 1,403.2 $ 592.1 $ 474.2 $ 4,679.9 Interest accretion $ 137.6 $ 15.8 $ 42.9 $ 86.9 $ 283.2 September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 6,001.5 $ 977.0 $ 5,579.6 $ 5,082.2 $ 17,640.3 Expected future gross premiums $ — $ — $ 5,822.4 $ 5,817.0 $ 11,639.4 Amount of discounted (at interest accretion rate): Expected future gross premiums $ — $ — $ 3,854.6 $ 4,180.2 $ 8,034.8 Weighted average interest rate: Interest accretion rate 4.1 % 2.3 % 5.0 % 5.1 % 4.3 % Current discount rate 4.3 % 2.4 % 4.9 % 4.6 % 4.3 % Weighted average duration of the liability 4.2 years 2.5 years 18.5 years 9.4 years 7.1 years September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 6,474.2 $ 1,069.2 $ 5,107.4 $ 5,292.7 $ 17,943.5 Expected future gross premiums $ — $ — $ 5,317.5 $ 5,701.8 $ 11,019.3 Amount of discounted (at interest accretion rate): Expected future gross premiums $ — $ — $ 3,663.8 $ 4,099.5 $ 7,763.3 Weighted average interest rate: Interest accretion rate 4.0 % 2.3 % 5.0 % 5.1 % 4.2% Current discount rate 5.4 % 3.1 % 5.7 % 5.7 % 5.3% Weighted average duration of the liability 4.3 years 2.7 years 18.2 years 9.6 years 6.9 years Unum International Segment The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Unum International segment. September 30 2024 2023 (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 270.3 $ 197.1 Beginning balance at original discount rate 298.4 246.8 Effect of changes in cash flow assumptions (5.9) (5.1) Effect of actual variances from expected experience 15.1 12.2 Adjusted beginning of year balance 307.6 253.9 Issuances 1 25.3 16.9 Interest accretion 8.7 6.9 Net premiums collected (21.2) (16.9) Foreign currency 7.3 (0.1) Ending balance at original discount rate 327.7 260.7 Effect of change in discount rate assumptions (27.9) (37.6) Balance, end of period $ 299.8 $ 223.1 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 2,527.4 $ 2,231.4 Beginning balance at original discount rate 2,687.1 2,495.5 Effect of changes in cash flow assumptions 0.1 17.7 Effect of actual variances from expected experience (13.4) (9.2) Adjusted beginning of year balance 2,673.8 2,504.0 Issuances 1 300.3 277.3 Interest accretion 51.3 47.7 Benefit payments (326.4) (307.5) Foreign currency 121.0 19.6 Ending balance at original discount rate 2,820.0 2,541.1 Effect of change in discount rate assumptions (214.9) (297.1) Balance, end of period $ 2,605.1 $ 2,244.0 Net liability for future policy benefits $ 2,305.3 $ 2,020.9 Other 43.1 30.3 Total liability for future policy benefits 2,348.4 2,051.2 Less: Reinsurance recoverable related to future policy benefits 78.0 69.4 Net liability for future policy benefits, after reinsurance recoverable $ 2,270.4 $ 1,981.8 1 Issuances for Unum International primarily represent new claim incurrals. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Unum International segment presented in the rollforward activity above. Nine Months Ended September 30 2024 2023 (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 710.2 $ 667.7 Interest accretion $ 42.6 $ 40.8 September 30 2024 2023 (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 4,536.2 $ 4,012.8 Expected future gross premiums $ 1,335.6 $ 1,035.7 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 854.1 $ 676.8 Weighted average interest rate: Interest accretion rate 4.1 % 4.0 % Current discount rate 4.9 % 5.4 % Weighted average duration of the liability 8.9 years 8.6 years Colonial Life Segment The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Colonial Life segment. September 30 2024 2023 (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 3,592.6 $ 3,745.4 Beginning balance at original discount rate 3,754.3 4,046.4 Effect of changes in cash flow assumptions (7.9) (322.7) Effect of actual variances from expected experience (57.0) (77.1) Adjusted beginning of year balance 3,689.4 3,646.6 Issuances 417.2 421.7 Interest accretion 101.4 94.3 Net premiums collected (455.5) (454.0) Ending balance at original discount rate 3,752.5 3,708.6 Effect of change in discount rate assumptions (105.6) (348.7) Balance, end of period $ 3,646.9 $ 3,359.9 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 5,566.0 $ 5,581.1 Beginning balance at original discount rate 5,925.2 6,163.9 Effect of changes in cash flow assumptions (52.7) (402.9) Effect of actual variances from expected experience (84.2) (90.1) Adjusted beginning of year balance 5,788.3 5,670.9 Issuances 455.1 461.1 Interest accretion 172.2 161.0 Benefit payments (458.4) (462.1) Ending balance at original discount rate 5,957.2 5,830.9 Effect of change in discount rate assumptions (303.5) (731.9) Balance, end of period $ 5,653.7 $ 5,099.0 Net liability for future policy benefits $ 2,006.8 $ 1,739.1 Other 25.1 24.3 Total liability for future policy benefits 2,031.9 1,763.4 Less: Reinsurance recoverable related to future policy benefits 1.5 0.9 Net liability for future policy benefits, after reinsurance recoverable $ 2,030.4 $ 1,762.5 The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Colonial Life segment presented in the rollforward activity above. Nine Months Ended September 30 2024 2023 (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 1,286.4 $ 1,240.3 Interest accretion $ 70.8 $ 66.7 September 30 2024 2023 (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 10,242.2 $ 9,568.2 Expected future gross premiums $ 12,450.4 $ 11,847.5 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 8,948.9 $ 8,684.1 Weighted average interest rate: Interest accretion rate 4.4 % 4.3 % Current discount rate 4.8 % 5.7 % Weighted average duration of the liability 17.3 years 16.9 years Closed Block Segment The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Closed Block segment. September 30, 2024 Long-term Care All Other Total Closed Block (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 8,123.5 $ — $ 8,123.5 Beginning balance at original discount rate 7,703.6 — 7,703.6 Effect of changes in cash flow assumptions 145.5 — 145.5 Effect of actual variances from expected experience (32.6) — (32.6) Adjusted beginning of year balance 7,816.5 — 7,816.5 Interest accretion 302.0 — 302.0 Net premiums collected (462.3) — (462.3) Ending balance at original discount rate 7,656.2 — 7,656.2 Effect of change in discount rate assumptions 477.5 — 477.5 Balance, end of period $ 8,133.7 $ — $ 8,133.7 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 24,697.7 $ 7,880.0 $ 32,577.7 Beginning balance at original discount rate 22,649.3 8,094.6 30,743.9 Effect of changes in cash flow assumptions (4.1) 5.4 1.3 Effect of actual variances from expected experience 38.9 5.2 44.1 Adjusted beginning of year balance 22,684.1 8,105.2 30,789.3 Issuances 1 — 82.3 82.3 Interest accretion 899.7 261.6 1,161.3 Benefit payments (710.0) (738.6) (1,448.6) Ending balance at original discount rate 22,873.8 7,710.5 30,584.3 Effect of change in discount rate assumptions 1,927.3 (129.2) 1,798.1 Balance, end of period $ 24,801.1 $ 7,581.3 $ 32,382.4 Net liability for future policy benefits $ 16,667.4 $ 7,581.3 $ 24,248.7 Other 2 (0.7) 1,556.5 1,555.8 Total liability for future policy benefits 16,666.7 9,137.8 25,804.5 Less: Reinsurance recoverable related to future policy benefits 4.2 7,171.4 7,175.6 Net liability for future policy benefits, after reinsurance recoverable $ 16,662.5 $ 1,966.4 $ 18,628.9 1 Issuances for Closed Block - All Other represents new claim incurrals. 2 Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products. September 30, 2023 Long-term Care All Other Total Closed Block (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 6,412.6 $ — $ 6,412.6 Beginning balance at original discount rate 6,236.1 — 6,236.1 Effect of changes in cash flow assumptions 1,641.3 — 1,641.3 Effect of actual variances from expected experience 54.9 — 54.9 Adjusted beginning of year balance 7,932.3 — 7,932.3 Interest accretion 271.9 — 271.9 Net premiums collected (438.1) — (438.1) Ending balance at original discount rate 7,766.1 — 7,766.1 Effect of change in discount rate assumptions (141.1) — (141.1) Balance, end of period $ 7,625.0 $ — $ 7,625.0 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 21,199.9 $ 8,218.8 $ 29,418.7 Beginning balance at original discount rate 20,221.6 8,630.7 28,852.3 Effect of changes in cash flow assumptions 2,009.4 — 2,009.4 Effect of actual variances from expected experience 106.7 4.1 110.8 Adjusted beginning of year balance 22,337.7 8,634.8 30,972.5 Issuances 1 — 101.2 101.2 Interest accretion 850.7 270.0 1,120.7 Benefit payments (624.2) (776.0) (1,400.2) Ending balance at original discount rate 22,564.2 8,230.0 30,794.2 Effect of change in discount rate assumptions (579.3) (687.0) (1,266.3) Balance, end of period $ 21,984.9 $ 7,543.0 $ 29,527.9 Net liability for future policy benefits $ 14,359.9 $ 7,543.0 $ 21,902.9 Other 2 12.8 1,606.0 1,618.8 Total liability for future policy benefits 14,372.7 9,149.0 23,521.7 Less: Reinsurance recoverable related to future policy benefits 4.6 7,173.7 7,178.3 Net liability for future policy benefits, after reinsurance recoverable $ 14,368.1 $ 1,975.3 $ 16,343.4 1 Issuances for Closed Block - All Other represents new claim incurrals. 2 Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Closed Block segment presented in the rollforward activity above. Nine Months Ended September 30, 2024 Long-term Care All Other Total Closed Block (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 521.6 $ 143.6 $ 665.2 Interest accretion $ 597.7 $ 261.6 $ 859.3 Nine Months Ended September 30, 2023 Long-term Care All Other Total Closed Block (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 521.2 $ 169.3 $ 690.5 Interest accretion $ 578.8 $ 270.0 $ 848.8 September 30, 2024 Long-term Care All Other Total Closed Block (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 60,339.0 $ 11,281.4 $ 71,620.4 Expected future gross premiums $ 13,968.7 $ — $ 13,968.7 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 8,103.6 $ — $ 8,103.6 Weighted average interest rate: Interest accretion rate 5.6 % 4.6 % 5.2 % Current discount rate 5.0 % 4.7 % 4.9 % Weighted average duration of the liability 15.9 years 7.2 years 13.0 years September 30, 2023 Long-term Care All Other Total Closed Block (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 61,672.0 $ 12,109.6 $ 73,781.6 Expected future gross premiums $ 14,678.9 $ — $ 14,678.9 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 8,311.0 $ — $ 8,311.0 Weighted average interest rate: Interest accretion rate 5.6 % 4.6 % 5.2% Current discount rate 5.8 % 5.7 % 5.8% Weighted average duration of the liability 16.6 years 7.3 years 13.3 years Reconciliation A reconciliation of the liability for future policy benefits reflected in the preceding rollforwards to the related liability balances in the consolidated balance sheets are as follows: September 30 2024 2023 (in millions of dollars) Liability for future policy benefits Unum US 1 $ 9,026.9 $ 8,930.0 Unum International 2,348.4 2,051.2 Colonial Life 2,031.9 1,763.4 Closed Block 1 25,804.5 23,521.7 Other products 1 232.8 236.1 Total liability for future policy benefits $ 39,444.5 $ 36,502.4 1 Unum US excludes dental & vision and medical stop-loss product lines and Closed Block excludes our participating fund account, which represents policies issued by one of our subsidiaries prior to its 1986 conversion from a mutual stock life insurance company. The liabilities associated with these products are included within Other products. Policyholders' account balances primarily include our universal life and corporate-owned life insurance products. Policyholders' account balances reflect customer deposits and interest credited less cost of insurance, administration expenses, surrender charges, and customer withdrawals. The following table presents the balances and changes in the policyholders' account balances: September 30, 2024 Unum US - Voluntary Benefits Colonial Life Closed Block - All Other Total (in millions of dollars, except weighted average data) Balance, beginning of year $ 578.6 $ 852.9 $ 4,082.7 $ 5,514.2 Premiums received 40.7 60.2 23.3 124.2 Policy charges 1 (42.9) (54.2) (73.7) (170.8) Surrenders and withdrawals (24.3) (30.4) (9.8) (64.5) Benefit payments (4.8) (6.0) (157.1) (167.9) Interest credited 15.7 25.6 220.1 261.4 Other 7.6 0.2 0.8 8.6 Balance, end of period 570.6 848.3 4,086.3 5,505.2 Reserves in excess of account balance 104.4 14.5 37.2 156.1 Total policyholders' account balances 675.0 862.8 4,123.5 5,661.3 Less: Reinsurance recoverable related to policyholders' account balances 0.8 — 4,123.5 4,124.3 Net policyholders' account balances, after reinsurance recoverable $ 674.2 $ 862.8 $ — $ 1,537.0 Weighted average crediting rate 3.7% 4.1% 7.4% 6.5% Net amount at risk 2 $ 4,210.4 $ 8,325.0 $ 1,698.7 $ 14,234.1 Cash surrender value $ 560.4 $ 817.1 $ 4,062.7 $ 5,440.2 1 Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance. 2 For those guarantees of benefits that are payable in the event of death, the net amount at risk is generally defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date. September 30, 2023 Unum US - Voluntary Benefits Colonial Life Closed Block - All Other Total (in millions of dollars, except weighted average data) Balance, beginning of year $ 586.8 $ 852.4 $ 4,159.4 $ 5,598.6 Premiums received 44.9 64.4 25.2 134.5 Policy charges 1 (45.8) (56.3) (78.9) (181.0) Surrenders and withdrawals (23.6) (28.5) (12.1) (64.2) Benefit payments (7.5) (5.6) (191.0) (204.1) Interest credited 17.0 25.7 239.0 281.7 Other 6.7 (0.2) 24.3 30.8 Balance, end of period 578.5 851.9 4,165.9 5,596.3 Reserves in excess of account balance 99.2 16.6 32.4 148.2 Total policyholders' account balances 677.7 868.5 4,198.3 5,744.5 Less: Reinsurance recoverable related to policyholders' account balances 1.0 — 4,198.3 4,199.3 Net policyholders' account balances, after reinsurance recoverable $ 676.7 $ 868.5 $ — $ 1,545.2 Weighted average crediting rate 4.0% 4.1% 8.0% 6.9% Net amount at risk 2 $ 4,600.0 $ 8,901.6 $ 1,807.1 $ 15,308.7 Cash surrender value $ 568.9 $ 810.1 $ 4,033.4 $ 5,412.4 1 Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance. 2 For those guarantees of benefits that are payable in the event of death, the net amount at risk is generally defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date. The balance of the account values by range of guaranteed minimum crediting rates and the related range of difference, in basis points, between rates being credited to policyholders and the respective guaranteed minimums is as follows. September 30, 2024 Range of Guaranteed Minimum Crediting Ra
Deferred Policy Acquisition Costs by Segment	Note 9 - Deferred Acquisition Costs During the third quarters of 2024 and 2023, we updated our policyholder lapse and mortality assumptions used to develop the future amortization for DAC for the Unum US voluntary benefits product line and the Colonial Life segment. These assumption updates were consistent with the related assumption updates for the liability for future policy benefits. The following tables display the changes in DAC throughout the period: September 30, 2024 Unum US Unum International Colonial Life Total (in millions of dollars) Balance, beginning of year $ 1,232.2 $ 46.9 $ 1,435.4 $ 2,714.5 Capitalization 247.4 13.2 234.7 495.3 Amortization expense (216.7) (7.3) (163.9) (387.9) Foreign currency — 1.6 — 1.6 Balance, end of period $ 1,262.9 $ 54.4 $ 1,506.2 $ 2,823.5 September 30, 2023 Unum US Unum International Colonial Life Total (in millions of dollars) Balance, beginning of year $ 1,185.1 $ 37.0 $ 1,337.9 $ 2,560.0 Capitalization 230.6 10.8 226.1 467.5 Amortization expense (199.2) (6.1) (153.4) (358.7) Foreign currency — (0.1) — (0.1) Balance, end of period $ 1,216.5 $ 41.6 $ 1,410.6 $ 2,668.7 September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Dental and Vision Total Unum US (in millions of dollars) Balance, beginning of year $ 63.6 $ 48.9 $ 610.6 $ 497.8 $ 11.3 $ 1,232.2 Capitalization 48.1 31.0 93.2 63.9 11.2 247.4 Amortization expense (46.8) (26.7) (88.4) (45.3) (9.5) (216.7) Balance, end of period $ 64.9 $ 53.2 $ 615.4 $ 516.4 $ 13.0 $ 1,262.9 September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Dental and Vision Total Unum US (in millions of dollars) Balance, beginning of year $ 61.0 $ 49.3 $ 601.0 $ 464.4 $ 9.4 $ 1,185.1 Capitalization 44.7 28.9 85.2 62.6 9.2 230.6 Amortization expense (42.1) (29.5) (79.5) (40.2) (7.9) (199.2) Balance, end of period $ 63.6 $ 48.7 $ 606.7 $ 486.8 $ 10.7 $ 1,216.5

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Segment Information	We have three principal operating business segments: Unum US, Unum International, and Colonial Life. Our other segments are Closed Block and Corporate. Segment information is shown below. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Premium Income Unum US Group Disability Group Long-term Disability $ 522.1 $ 518.5 $ 1,560.3 $ 1,539.3 Group Short-term Disability 271.3 256.5 810.7 753.0 Group Life and Accidental Death & Dismemberment Group Life 447.8 423.0 1,337.9 1,254.3 Accidental Death & Dismemberment 47.1 44.1 139.3 131.2 Supplemental and Voluntary Voluntary Benefits 219.3 209.5 665.1 637.4 Individual Disability 140.4 136.7 424.6 386.7 Dental and Vision 75.5 69.4 223.9 206.8 1,723.5 1,657.7 5,161.8 4,908.7 Unum International Unum UK Group Long-term Disability 106.6 101.1 312.4 297.5 Group Life 58.8 44.2 156.3 124.5 Supplemental 41.4 34.6 125.1 99.9 Unum Poland 39.8 30.7 113.3 85.2 246.6 210.6 707.1 607.1 Colonial Life Accident, Sickness, and Disability 240.6 236.7 725.5 708.0 Life 113.1 106.2 342.6 318.1 Cancer and Critical Illness 88.2 88.3 266.9 265.2 441.9 431.2 1,335.0 1,291.3 Closed Block Long-term Care 173.7 172.1 521.5 521.2 All Other 43.1 54.3 140.9 166.0 216.8 226.4 662.4 687.2 Total Premium Income $ 2,628.8 $ 2,525.9 $ 7,866.3 $ 7,494.3 Unum US Unum International Colonial Life Closed Block Corporate Total (in millions of dollars) Three Months Ended September 30, 2024 Premium Income $ 1,723.5 $ 246.6 $ 441.9 $ 216.8 $ — $ 2,628.8 Net Investment Income 161.0 30.4 39.6 284.3 12.5 527.8 Other Income 60.1 0.4 0.4 12.4 — 73.3 Adjusted Operating Revenue $ 1,944.6 $ 277.4 $ 481.9 $ 513.5 $ 12.5 $ 3,229.9 Adjusted Operating Income (Loss) $ 363.3 $ 40.3 $ 113.4 $ 34.2 $ (49.4) $ 501.8 Three Months Ended September 30, 2023 Premium Income $ 1,657.7 $ 210.6 $ 431.2 $ 226.4 $ — $ 2,525.9 Net Investment Income 166.2 27.3 39.3 274.9 18.3 526.0 Other Income 58.0 0.5 0.3 12.8 — 71.6 Adjusted Operating Revenue $ 1,881.9 $ 238.4 $ 470.8 $ 514.1 $ 18.3 $ 3,123.5 Adjusted Operating Income (Loss) $ 357.8 $ 36.8 $ 102.9 $ 34.2 $ (41.5) $ 490.2 Unum US Unum International Colonial Life Closed Block Corporate Total (in millions of dollars) Nine Months Ended September 30, 2024 Premium Income $ 5,161.8 $ 707.1 $ 1,335.0 $ 662.4 $ — $ 7,866.3 Net Investment Income 476.1 94.5 119.4 851.6 44.8 1,586.4 Other Income 178.9 1.2 3.6 37.7 1.1 222.5 Adjusted Operating Revenue $ 5,816.8 $ 802.8 $ 1,458.0 $ 1,551.7 $ 45.9 $ 9,675.2 Adjusted Operating Income (Loss) $ 1,106.0 $ 120.2 $ 344.0 $ 110.1 $ (140.8) $ 1,539.5 Nine Months Ended September 30, 2023 Premium Income $ 4,908.7 $ 607.1 $ 1,291.3 $ 687.2 $ — $ 7,494.3 Net Investment Income 481.5 104.0 114.6 796.0 69.8 1,565.9 Other Income 166.1 1.0 0.9 40.1 2.5 210.6 Adjusted Operating Revenue $ 5,556.3 $ 712.1 $ 1,406.8 $ 1,523.3 $ 72.3 $ 9,270.8 Adjusted Operating Income (Loss) $ 1,013.4 $ 118.7 $ 312.3 $ 143.6 $ (109.9) $ 1,478.1 September 30 December 31 2024 2023 (in millions of dollars) Assets Unum US $ 15,365.4 $ 15,561.1 Unum International 3,569.4 3,372.9 Colonial Life 4,994.2 4,830.4 Closed Block 35,527.4 35,272.8 Corporate 4,684.1 4,218.0 Total Assets $ 64,140.5 $ 63,255.2 We measure and analyze our segment performance on the basis of "adjusted operating revenue" and "adjusted operating income" or "adjusted operating loss", which differ from total revenue and income before income tax as presented in our consolidated statements of income due to the exclusion of investment gains or losses, the amortization of the cost of reinsurance, the impact of non-contemporaneous reinsurance, and reserve assumption updates as well as certain other items as specified in the reconciliations below. We believe adjusted operating revenue and adjusted operating income or loss are better performance measures and better indicators of the revenue and profitability and underlying trends in our business. These performance measures are in accordance with GAAP guidance for segment reporting, but they should not be viewed as a substitute for total revenue, income before income tax, net income, or net loss. Investment gains or losses primarily include realized investment gains or losses, expected investment credit losses, and gains or losses on derivatives. Investment gains or losses depend on market conditions and do not necessarily relate to decisions regarding the underlying business of our segments. Our investment focus is on investment income to support our insurance liabilities as opposed to the generation of investment gains or losses. Although we may experience investment gains or losses which will affect future earnings levels, a long-term focus is necessary to maintain profitability over the life of the business since our underlying business is long-term in nature, and we need to earn the interest rates assumed in calculating our liabilities. Cash flow assumptions used to calculate our liability for future policy benefits are reviewed at least annually and updated, as needed, with the resulting impact reflected in net income. While the effects of these assumption updates are recorded in the reporting period in which the review is completed, these updates reflect experience emergence and changes to expectations spanning multiple periods. We believe that by excluding the impact of reserve assumption updates we are providing a more comparable and consistent view of our quarterly results. We exited a substantial portion of our Closed Block individual disability product line through the two phases of the reinsurance transaction that were executed in December 2020 and March 2021. As a result, we exclude the amortization of the cost of reinsurance that we recognized upon the exit of the business related to the policies on claim status as well as the impact of non-contemporaneous reinsurance that resulted from the adoption of ASU 2018-12. Due to the execution of the second phase of the reinsurance transaction occurring after January 1, 2021, the transition date of ASU 2018-12, in accordance with the provisions of the ASU related to non-contemporaneous reinsurance, we were required to establish the ceded reserves using an upper-medium grade fixed-income instrument as of the reinsurance transaction date in March 2021 which resulted in higher ceded reserves compared to that which was reported historically. However, the direct reserves for the block reinsured in the second phase were calculated using the original discount rate utilized as of the transition date. Both the direct and ceded reserves are then remeasured at each reporting period using a current discount rate reflective of an upper-medium grade fixed-income instrument, with the changes recognized in OCI. While the total equity impact is neutral, the different original discount rates utilized for direct and ceded reserves result in disproportionate earnings impacts. The impact of non-contemporaneous reinsurance will fluctuate depending on the magnitude of reserve changes during the period. We believe that the exclusion of these items provides a better view of our results from our ongoing businesses. We may at other times exclude certain other items from our discussion of financial ratios and metrics in order to enhance the understanding and comparability of our operational performance and the underlying fundamentals, but this exclusion is not an indication that similar items may not recur and does not replace net income or net loss as a measure of our overall profitability. A reconciliation of total revenue to "adjusted operating revenue" and income before income tax to "adjusted operating income" is as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Total Revenue $ 3,217.0 $ 3,092.5 $ 9,650.7 $ 9,240.8 Excluding: Net Investment Loss (12.9) (31.0) (24.5) (30.0) Adjusted Operating Revenue $ 3,229.9 $ 3,123.5 $ 9,675.2 $ 9,270.8 Income Before Income Tax $ 814.6 $ 261.7 $ 1,805.8 $ 1,211.4 Excluding: Net Investment Loss (12.9) (31.0) (24.5) (30.0) Amortization of the Cost of Reinsurance (10.4) (11.1) (31.1) (33.1) Non-Contemporaneous Reinsurance (6.0) (9.2) (20.2) (26.4) Reserve Assumption Updates 357.4 (177.2) 357.4 (177.2) Loss on Legal Settlement (15.3) — (15.3) — Adjusted Operating Income $ 501.8 $ 490.2 $ 1,539.5 $ 1,478.1

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2024
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits Disclosure	Defined Benefit Pension and Other Postretirement Benefit (OPEB) Plans We sponsor several defined benefit pension and OPEB plans for our employees, including non-qualified pension plans. The U.S. qualified and non-qualified defined benefit pension plans comprise the majority of our total benefit obligation and benefit cost. We maintain a separate defined benefit plan for eligible employees in our U.K. operation. The U.S. defined benefit pension plans were closed to new entrants on December 31, 2013, the OPEB plan was closed to new entrants on December 31, 2012, and the U.K. plan was closed to new entrants on December 31, 2002. The following table provides the components of the net periodic benefit cost (credit) for the defined benefit pension and OPEB plans. Three Months Ended September 30 Pension Benefits U.S. Plans U.K. Plan OPEB 2024 2023 2024 2023 2024 2023 (in millions of dollars) Service Cost $ 2.3 $ 2.3 $ — $ — $ — $ — Interest Cost 20.7 22.0 1.9 1.9 1.0 1.1 Expected Return on Plan Assets (22.8) (23.0) (2.1) (2.1) (0.1) (0.2) Amortization of: Net Actuarial (Gain) Loss 3.7 3.8 0.7 0.6 (0.2) (2.6) Prior Service Credit — — — — (0.1) — Total Net Periodic Benefit Cost (Credit) $ 3.9 $ 5.1 $ 0.5 $ 0.4 $ 0.6 $ (1.7) Nine Months Ended September 30 Pension Benefits U.S. Plans U.K. Plan OPEB 2024 2023 2024 2023 2024 2023 (in millions of dollars) Service Cost $ 6.9 $ 6.9 $ — $ — $ — $ — Interest Cost 62.1 66.0 5.7 5.7 3.0 3.4 Expected Return on Plan Assets (68.4) (69.1) (6.3) (6.3) (0.3) (0.4) Amortization of: Net Actuarial (Gain) Loss 11.0 11.4 2.2 1.9 (0.8) (7.9) Prior Service Credit — — — — (0.2) (0.1) Total Net Periodic Benefit Cost (Credit) $ 11.6 $ 15.2 $ 1.6 $ 1.3 $ 1.7 $ (5.0) The service cost component of net periodic pension and postretirement benefit cost (credit) is included as a component of compensation expense in our consolidated statements of income. All other components of net periodic pension and postretirement benefit cost (credit) are included in other expenses.

Stockholders' Equity and Earnin

Stockholders' Equity and Earnings Per Common Share	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity and Earnings Per Common Share [Abstract]
Earnings Per Share Disclosure	Earnings Per Common Share Net income per common share is determined as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars, except share data) Numerator Net Income $ 645.7 $ 202.0 $ 1,430.4 $ 953.2 Denominator (000s) Weighted Average Common Shares - Basic 186,400.7 196,083.2 189,665.1 197,289.5 Dilution for Assumed Exercises of Nonvested Stock Awards 481.7 1,048.6 544.6 1,005.6 Weighted Average Common Shares - Assuming Dilution 186,882.4 197,131.8 190,209.7 198,295.1 Net Income Per Common Share Basic $ 3.46 $ 1.03 $ 7.54 $ 4.83 Assuming Dilution $ 3.46 $ 1.02 $ 7.52 $ 4.81 We compute basic earnings per share by dividing net income by the weighted average number of common shares outstanding for the period. In computing earnings per share assuming dilution, we include potential common shares that are dilutive (those that reduce earnings per share). We use the treasury stock method to account for the effect of nonvested stock success units and nonvested restricted stock units on the computation of diluted earnings per share. Under this method, the potential common shares from nonvested stock success units and nonvested restricted stock units will each have a dilutive effect, as individually measured, when the average market price of Unum Group common stock during the period exceeds the grant price of the nonvested stock success units and nonvested restricted stock units. The outstanding nonvested stock success units and nonvested restricted stock units have grant prices ranging from $18.78 to $52.40. Potential common shares not included in the computation of diluted earnings per share because the impact would be antidilutive were zero and 0.2 million for the three and nine months ended September 30, 2024, respectively. There were a de minimis amount and 0.4 million potential common shares that were antidilutive for the three and nine months ended September 30, 2023, respectively.
Stockholders' Equity Disclosure	Common Stock As part of our capital deployment strategy, we may repurchase shares of Unum Group's common stock, as authorized by our board of directors. The timing and amount of repurchase activity is based on market conditions and other considerations, including the level of available cash, alternative uses for cash, and our stock price. Our board of directors has authorized the following repurchase programs: July 2024 Authorization October 2023 Authorization 1 December 2022 Authorization 2 (in millions) Effective Date August 1, 2024 January 1, 2024 January 1, 2023 Expiration Date None July 31, 2024 December 31, 2023 Authorized Repurchase Amount $ 1,000.0 $ 500.0 $ 250.0 Cost of Shares Repurchased Under Repurchase Program 35.8 464.2 250.0 Unused and Expired — 35.8 — Remaining Repurchase Amount at September 30, 2024 $ 964.2 $ — $ — 1 Concurrent with the announcement of the July 2024 repurchase program, we also announced the termination of the October 2023 program as of July 31, 2024, and all unused amounts under that program expired as of that date. 2 In February 2023, the December 2022 program was modified to increase the authorized repurchase amount from $200.0 million to $250.0 million. In August 2022, the Inflation Reduction Act was signed into law in the U.S. and imposes a one percent excise tax on corporate stock repurchases effective January 1, 2023. This excise tax is recorded as part of the cost basis of treasury stock and is assessed on the fair market value of stock repurchases reduced by the fair market value of any shares issued during the period. Common stock repurchases, which are accounted for using the cost method and classified as treasury stock until otherwise retired, were as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions) Shares Repurchased 3.7 1.5 9.7 3.9 Cost of Shares Repurchased 1 $ 202.0 $ 74.8 $ 504.8 $ 175.4 1 Includes a de minimis amount of commissions for the three and nine months ended September 30, 2024 and a de minimis amount and $0.1 million of commissions for the three and nine months ended September 30, 2023, respectively. Also includes $2.0 million and $4.8 million of excise tax for the three and nine months ended September 30, 2024, respectively, and $0.7 million and $1.2 million of excise tax for the three and nine months ended September 30, 2023, respectively. As a part of our share repurchase program, we periodically enter into accelerated share repurchase agreements (ASR). Under the terms of these agreements, we make a prepayment to a financial counterparty for which we receive an initial delivery of approximately 75 percent of the total Unum Group common stock to be delivered under the agreement. We simultaneously enter into a forward contract indexed to the price of Unum Group common stock, which subjects the transactions to a future price adjustment. Under the terms of the agreements, we are to receive, or be required to pay, a price adjustment based on the volume weighted average price of Unum Group common stock during the term of the agreement, less a discount. Any price adjustment payable to us is settled in shares of Unum Group common stock. Any price adjustment we would be required to pay may be settled in either cash or common stock at our option. Details of our ASRs are as follows: Prepayment Date Prepayment Amount Initial Share Delivery Forward Contract Settlement Date Shares Delivered to Settle Forward Contract (in millions) October 2024 $150.0 1.9 December 2024 Not yet settled July 2024 $150.0 2.2 September 2024 0.6 April 2024 $125.0 1.7 June 2024 0.7 January 2024 $100.0 1.6 March 2024 0.5 July 2023 $50.0 0.8 September 2023 0.2 Preferred Stock Unum Group has 25.0 million shares of preferred stock authorized with a par value of $0.10 per share. No preferred stock has been issued to date.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure	Commitments See Notes 3 and 4 for further discussion on certain of our investment commitments. Contingent Liabilities We are a defendant in a number of litigation matters that have arisen in the normal course of business, including the matters discussed below. Further, state insurance regulatory authorities and other federal and state authorities regularly make inquiries and conduct investigations concerning our compliance with applicable insurance and other laws and regulations. Given the complexity and scope of our litigation and regulatory matters, it is not possible to predict the ultimate outcome of all pending investigations or legal proceedings or provide reasonable estimates of potential losses, except if noted in connection with specific matters. In some of these matters, no specified amount is sought. In others, very large or indeterminate amounts, including punitive and treble damages, are asserted. There is a wide variation of pleading practice permitted in the United States courts with respect to requests for monetary damages, including some courts in which no specified amount is required and others which allow the plaintiff to state only that the amount sought is sufficient to invoke the jurisdiction of that court. Further, some jurisdictions permit plaintiffs to allege damages well in excess of reasonably possible verdicts. Based on our extensive experience and that of others in the industry with respect to litigating or resolving claims through settlement over an extended period of time, we believe that the monetary damages asserted in a lawsuit or claim bear little relation to the merits of the case, or the likely disposition value. Therefore, the specific monetary relief sought is not stated. Unless indicated otherwise, reserves have not been established for litigation and contingencies. An estimated loss is accrued when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Claim Handling Matters We and our insurance subsidiaries, in the ordinary course of our business, are engaged in claim litigation where disputes arise as a result of a denial or termination of benefits. Most typically these lawsuits are filed on behalf of a single claimant or policyholder, and in some of these individual actions punitive damages are sought, such as claims alleging bad faith in the handling of insurance claims. For our general claim litigation, we maintain reserves based on experience to satisfy judgments and settlements in the normal course. We expect that the ultimate liability, if any, with respect to general claim litigation, after consideration of the reserves maintained, will not be material to our consolidated financial condition. Nevertheless, given the inherent unpredictability of litigation, it is possible that an adverse outcome in certain claim litigation involving punitive damages could, from time to time, have a material adverse effect on our consolidated results of operations in a period, depending on the results of operations for the particular period. From time to time class action allegations are pursued where the claimant or policyholder purports to represent a larger number of individuals who are similarly situated. Since each insurance claim is evaluated based on its own merits, there is rarely a single act or series of actions which can properly be addressed by a class action. Nevertheless, we monitor these cases closely and defend ourselves appropriately where these allegations are made.

Other

Other	9 Months Ended
	Sep. 30, 2024
Debt and Other Disclosures [Abstract]
Debt	Debt In June 2024, we issued $400.0 million of 6.000% senior notes due 2054. The notes are callable at or above par and rank equally in the right of payment with all of our other unsecured and unsubordinated debt. A portion of the net proceeds of the offering were used to repay the $350.0 million aggregate principal amount of outstanding indebtedness under our senior unsecured delayed draw term loan facility, which was terminated upon repayment. P-Caps Trust During November 2021, we entered into a 20-year facility agreement with a Delaware statutory trust (the P-Caps Trust), in connection with the sale by the P-Caps Trust of $400.0 million of pre-capitalized trust securities (P-Caps) in a Rule 144A private placement. The P-Caps Trust invested the proceeds from the sale of the P-Caps in a portfolio of principal and interest strips of U.S. Treasury securities (the Trust Assets). The facility agreement gave us the right to issue and require the P-Caps Trust to purchase, on one or more occasions, up to $400.0 million of our 4.046% senior notes due 2041 (the 2041 Senior Notes) in exchange for the Trust Assets. Under the facility agreement, we agreed to pay a semi-annual facility fee to the P-Caps Trust at a rate of 2.225% per year on the unexercised portion of the maximum amount of 2041 senior notes that we could issue and sell to the P-Caps Trust and to reimburse the P-Caps Trust for its expenses. In October 2024, we exercised our issuance right in full under the facility agreement and issued $400.0 million of the 2041 Senior Notes to the P-Caps Trust in exchange for the Trust Assets, thereby triggering our recognition of the 2041 Senior Notes on our consolidated balance sheets. The Trust Assets had a fair value of $273.5 million when the 2041 Senior Notes were issued. We directed the trustee of the P-Caps Trust to dissolve the P-Caps Trust and to deliver the 2041 Senior Notes to the beneficial holders of the P-Caps pro rata in respect of each P-Cap. The 2041 Senior Notes are callable at or above par and rank equally in the right of payment with all of our other unsecured and unsubordinated debt. The net proceeds from the issuance of the 2041 Senior Notes and subsequent sale of the Trust Assets are expected to be used for future share repurchases. We have an additional five-year, £75 million senior standby letter of credit facility pursuant to which a standby letter of credit was issued in favor of Unum Limited (as beneficiary), our U.K. insurance subsidiary, and is available for drawings up to £75.0 million until its scheduled expiration in December 2028. In connection with and as security for the senior standby letter of credit facility, we granted to the issuer of the standby letter of credit the right to exercise, if an event of default occurred and was continuing, the issuance right under the facility agreement with the P-Caps Trust, up to a maximum of $200.0 million. In October 2024, prior to our exercise of the issuance right under the facility agreement, the assigned issuance right was forfeited in its entirety. For further information see "Liquidity and Capital Resources - Debt, Term Loan Facility, Credit Facilities and Other Sources of Liquidity" in Part I, Item 2.
Allowance for Expected Credit Losses on Premiums Receivable	Allowance for Expected Credit Losses on Premiums Receivable At September 30, 2024, June 30, 2024, and December 31, 2023, the allowance for expected credit losses on premiums receivable was $27.1 million, $26.8 million, and $29.5 million, respectively, on gross premiums receivable of $630.4 million, $659.8 million, and $612.4 million, respectively. The allowance for expected credit losses was generally consistent at September 30, 2024 compared to June 30, 2024. The decrease of $2.4 million during the nine months ended September 30, 2024 was driven primarily by improvements in the age of gross premiums receivable.
Loss on Legal Settlement	Loss on Legal Settlement During the third quarter of 2024, we incurred a loss of $15.3 million within our Corporate segment for the settlement of an employment-related matter. $4.9 million of the loss is recorded within compensation expense and $10.4 million of the loss is recorded within other expenses within the consolidated statements of income.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income	$ 645.7	$ 202	$ 1,430.4	$ 953.2

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Arrangement Duration	25 days

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	The accompanying consolidated financial statements of Unum Group and its subsidiaries (the Company) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. For further information, refer to the consolidated financial statements and footnotes included in our annual report on Form 10-K for the year ended December 31, 2023.

Fair Values of Financial Inst_2

Fair Values of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share	The following tables present additional information about our private equity partnerships, including commitments for additional investments which may or may not be funded: September 30, 2024 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 246.3 Not redeemable $ 126.1 50.7 Quarterly / 90 days notice 6.2 Total Private Credit 297.0 132.3 Private Equity (b) 574.8 Not redeemable 417.2 33.3 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 13.2 Total Private Equity 608.1 430.4 Real Assets (c) 488.8 Not redeemable 242.9 34.1 Quarterly / 90 days notice — Total Real Assets 522.9 242.9 Total Partnerships $ 1,428.0 $ 805.6 December 31, 2023 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 239.1 Not redeemable $ 128.2 44.5 Quarterly / 90 days notice 8.6 Total Private Credit 283.6 136.8 Private Equity (b) 543.9 Not redeemable 410.6 28.0 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 16.6 Total Private Equity 571.9 427.2 Real Assets (c) 437.5 Not redeemable 239.1 33.2 Quarterly / 90 days notice — Total Real Assets 470.7 239.1 Total Partnerships $ 1,326.2 $ 803.1 (a) Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North America and, to a lesser extent, outside of North America. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 80 percent in the next 3 years, 12 percent during the period from 3 to 5 years, and 8 percent during the period from 5 to 10 years. (b) Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 36 percent in the next 3 years, 31 percent during the period from 3 to 5 years, and 33 percent during the period from 5 to 10 years. (c) Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 38 percent in the next 3 years, 26 percent during period from 3 to 5 years, 34 percent during the period from 5 to 10 years, and 2 percent during the period from 10 to 15 years.
Fair Values by Fair Value Hierarchy Input level	The following tables present information about financial instruments measured at fair value on a recurring basis by fair value level, based on the observability of the inputs used: September 30, 2024 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ — $ 557.4 $ — $ — $ 557.4 States, Municipalities, and Political Subdivisions — 3,526.5 — — 3,526.5 Foreign Governments — 850.1 — — 850.1 Public Utilities 602.7 4,982.5 — — 5,585.2 Mortgage/Asset-Backed Securities — 799.6 51.0 — 850.6 All Other Corporate Bonds 7,362.2 19,015.8 28.0 — 26,406.0 Redeemable Preferred Stocks — 7.7 — — 7.7 Total Fixed Maturity Securities 7,964.9 29,739.6 79.0 — 37,783.5 Other Long-term Investments Derivatives Forwards — 49.5 — — 49.5 Foreign Currency Interest Rate Swaps — 56.0 — — 56.0 Embedded Derivative in Modified Coinsurance Arrangement — — 4.6 — 4.6 Total Derivatives — 105.5 4.6 — 110.1 Perpetual Preferred and Equity Securities — 0.1 21.7 — 21.8 Private Equity Partnerships — — — 1,428.0 1,428.0 Total Other Long-term Investments — 105.6 26.3 1,428.0 1,559.9 Total Financial Instrument Assets Carried at Fair Value $ 7,964.9 $ 29,845.2 $ 105.3 $ 1,428.0 $ 39,343.4 Liabilities Other Liabilities Derivatives Forwards $ — $ 95.2 $ — $ — $ 95.2 Foreign Currency Interest Rate Swaps — 35.0 — — 35.0 Total Derivatives — 130.2 — — 130.2 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 130.2 $ — $ — $ 130.2 December 31, 2023 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ — $ 624.8 $ — $ — $ 624.8 States, Municipalities, and Political Subdivisions — 3,678.4 — — 3,678.4 Foreign Governments — 890.7 — — 890.7 Public Utilities 301.3 5,020.3 — — 5,321.6 Mortgage/Asset-Backed Securities — 611.2 32.9 — 644.1 All Other Corporate Bonds 3,985.2 21,562.1 123.4 — 25,670.7 Redeemable Preferred Stocks — 3.6 — — 3.6 Total Fixed Maturity Securities 4,286.5 32,391.1 156.3 — 36,833.9 Other Long-term Investments Derivatives Forwards — 47.5 — — 47.5 Foreign Currency Interest Rate Swaps — 52.4 — — 52.4 Total Derivatives — 99.9 — — 99.9 Perpetual Preferred and Equity Securities — 10.3 21.6 — 31.9 Private Equity Partnerships — — — 1,326.2 1,326.2 Total Other Long-term Investments — 110.2 21.6 1,326.2 1,458.0 Total Financial Instrument Assets Carried at Fair Value $ 4,286.5 $ 32,501.3 $ 177.9 $ 1,326.2 $ 38,291.9 Liabilities Other Liabilities Derivatives Forwards $ — $ 78.0 $ — $ — $ 78.0 Foreign Currency Interest Rate Swaps — 38.2 — — 38.2 Embedded Derivative in Modified Coinsurance Arrangement — — 1.5 — 1.5 Total Derivatives — 116.2 1.5 — 117.7 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 116.2 $ 1.5 $ — $ 117.7
Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs	Changes in assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) are as follows: Three Months Ended September 30, 2024 Fair Value Beginning of Period Total Realized Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities Public Utilities $ — $ (0.2) $ 0.7 $ — $ (10.3) $ 9.8 $ — $ — $ — $ — Mortgage/Asset-Backed Securities 46.5 — 0.2 4.9 (0.7) 0.1 — 51.0 0.2 — All Other Corporate Bonds 53.3 — 2.0 — (42.2) 39.1 (24.2) 28.0 2.0 — Total Fixed Maturity Securities 99.8 (0.2) 2.9 4.9 (53.2) 49.0 (24.2) 79.0 2.2 — Perpetual Preferred and Equity Securities 21.7 — — — — — — 21.7 — — Embedded Derivative in Modified Coinsurance Arrangement 5.4 (0.8) — — — — — 4.6 — (0.8) Three Months Ended September 30, 2023 Fair Value Beginning of Period Total Realized and Unrealized Investment Gains (Losses) in Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities Public Utilities $ — $ (0.1) $ 0.1 $ — $ (3.9) $ 3.9 $ — $ — $ — $ — Mortgage/Asset-Backed Securities 24.1 — (1.4) 19.0 (1.0) 4.7 (0.2) 45.2 (1.4) — All Other Corporate Bonds 128.8 (4.6) 2.0 — (54.9) 87.5 (50.5) 108.3 2.0 — Total Fixed Maturity Securities 152.9 (4.7) 0.7 19.0 (59.8) 96.1 (50.7) 153.5 0.6 — Perpetual Preferred and Equity Securities 17.5 — — — — — — 17.5 — — Embedded Derivative in Modified Coinsurance Arrangement (8.4) 9.3 — — — — — 0.9 — 9.3 Nine Months Ended September 30, 2024 Fair Value Beginning of Year Total Realized Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities Public Utilities $ — $ (0.2) $ 0.3 $ — $ (10.3) $ 10.2 $ — $ — $ — $ — Mortgage/Asset-Backed Securities 32.9 — 0.6 15.5 (1.9) 3.9 — 51.0 0.6 — All Other Corporate Bonds 123.4 (2.6) 6.9 2.3 (196.4) 189.0 (94.6) 28.0 6.9 (2.6) Total Fixed Maturity Securities 156.3 (2.8) 7.8 17.8 (208.6) 203.1 (94.6) 79.0 7.5 (2.6) Perpetual Preferred and Equity Securities 21.6 0.1 — — — — — 21.7 — 0.1 Embedded Derivative in Modified Coinsurance Arrangement (1.5) 6.1 — — — — — 4.6 — 6.1 Nine Months Ended September 30, 2023 Fair Value Beginning of Year Total Realized and Unrealized Investment Gains (Losses) in Level 3 Transfers Fair Value End of Period Change in Unrealized Gain (Loss) on Securities Held at the End of Period included in Earnings OCI Purchases Sales/Maturities Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities States, Municipalities, and Political Subdivisions $ 0.2 $ — $ — $ — $ — $ — $ (0.2) $ — $ — $ — Public Utilities — 0.1 (0.1) — (7.2) 7.2 — — — — Mortgage/Asset-Backed Securities 22.0 — (1.5) 29.9 (2.8) 6.6 (9.0) 45.2 (1.5) — All Other Corporate Bonds 158.7 (5.1) (20.6) 1.5 (229.8) 276.0 (72.4) 108.3 (20.6) — Total Fixed Maturity Securities 180.9 (5.0) (22.2) 31.4 (239.8) 289.8 (81.6) 153.5 (22.1) — Perpetual Preferred and Equity Securities 16.2 0.6 — 0.7 — — — 17.5 — 0.6 Embedded Derivative in Modified Coinsurance Arrangement (13.9) 14.8 — — — — — 0.9 — 14.8
Quantitative Information Regarding Significant Unobservable Inputs	The table below provides quantitative information regarding the significant unobservable inputs used in Level 3 fair value measurements derived from internal models. Unobservable inputs for fixed maturity securities are weighted by the fair value of the securities. Certain securities classified as Level 3 are excluded from the table below due to limitations in our ability to obtain the underlying inputs used by external pricing sources. September 30, 2024 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 16.3 Market Approach Volatility of Credit Market Convention (a) (b) 5.00% - 5.00% / 5.00% Priced at Par Value Perpetual Preferred and Equity Securities 21.7 Market Approach Market Convention (b) Priced at Cost, Owner's Equity, or Most Recent Round Embedded Derivative in Modified Coinsurance Arrangement 4.6 Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (c) Actuarial Assumptions (0.031)% December 31, 2023 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 15.9 Market Approach Volatility of Credit Market Convention (a) (b) 5.00% - 5.00% / 5.00% Priced at Par Value Perpetual Preferred and Equity Securities 21.6 Market Approach Market Convention (b) Priced at Cost, Owner's Equity, or Most Recent Round Embedded Derivative in Modified Coinsurance Arrangement (1.5) Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (c) Actuarial Assumptions 0.2% (a) Represents basis point adjustments for credit-specific factors (b) Represents a decision to price based on par value, cost, owner's equity, or the price of the most recent capital funding round when limited data is available (c) Represents various actuarial assumptions required to derive the liability cash flows. Fair value of embedded derivative is most often driven by the change in the weighted average credit spread to the swap curve for the assets backing the hypothetical loan
Carrying Amount and Fair Value of Financial Instruments	The following table presents the carrying amounts and estimated fair values of our financial instruments not measured at fair value and indicates the level in the fair value hierarchy of the estimated fair value measurement based on the observability of the inputs used: September 30, 2024 Estimated Fair Value Level 1 Level 2 Level 3 Total Carrying Value (in millions of dollars) Assets Mortgage Loans $ — $ 2,041.8 $ — $ 2,041.8 $ 2,238.9 Policy Loans — — 3,708.6 3,708.6 3,625.6 Other Long-term Investments Miscellaneous Long-term Investments — 25.6 0.3 25.9 25.9 Total Financial Instrument Assets Not Carried at Fair Value $ — $ 2,067.4 $ 3,708.9 $ 5,776.3 $ 5,890.4 Liabilities Long-term Debt $ 3,347.8 $ 44.5 $ — $ 3,392.3 $ 3,470.4 Other Liabilities Unfunded Commitments — 0.2 — 0.2 0.2 Payable for Collateral on FHLB Funding Agreements — 299.0 — 299.0 299.0 Total Financial Instrument Liabilities Not Carried at Fair Value $ 3,347.8 $ 343.7 $ — $ 3,691.5 $ 3,769.6 December 31, 2023 Estimated Fair Value Level 1 Level 2 Level 3 Total Carrying Value (in millions of dollars) Assets Mortgage Loans $ — $ 2,070.7 $ — $ 2,070.7 $ 2,318.2 Policy Loans — — 3,696.3 3,696.3 3,620.2 Other Long-term Investments Miscellaneous Long-term Investments — 15.7 0.3 16.0 16.0 Total Financial Instrument Assets Not Carried at Fair Value $ — $ 2,086.4 $ 3,696.6 $ 5,783.0 $ 5,954.4 Liabilities Long-term Debt $ 2,629.1 $ 598.8 $ — $ 3,227.9 $ 3,430.4 Other Liabilities Unfunded Commitments — 0.2 — 0.2 0.2 Payable for Collateral on FHLB Funding Agreements — 64.5 — 64.5 64.5 Total Financial Instrument Liabilities Not Carried at Fair Value $ 2,629.1 $ 663.5 $ — $ 3,292.6 $ 3,495.1

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Amortized Cost and Fair Values of Securities by Security Type	At September 30, 2024 and December 31, 2023, all fixed maturity securities were classified as available-for-sale. The amortized cost and fair values of securities by security type are shown as follows: September 30, 2024 Amortized Cost, Gross of ACL 1 ACL 1 Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 542.5 $ — $ 28.8 $ 13.9 $ 557.4 States, Municipalities, and Political Subdivisions 3,843.4 — 118.7 435.6 3,526.5 Foreign Governments 964.8 — 22.4 137.1 850.1 Public Utilities 5,561.8 — 272.3 248.9 5,585.2 Mortgage/Asset-Backed Securities 853.8 — 13.2 16.4 850.6 All Other Corporate Bonds 27,048.3 2.9 882.8 1,522.2 26,406.0 Redeemable Preferred Stocks 8.0 — — 0.3 7.7 Total Fixed Maturity Securities $ 38,822.6 $ 2.9 $ 1,338.2 $ 2,374.4 $ 37,783.5 December 31, 2023 Amortized Cost, Gross of ACL 1 ACL 1 Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 618.6 $ — $ 25.3 $ 19.1 $ 624.8 States, Municipalities, and Political Subdivisions 4,041.3 — 135.3 498.2 3,678.4 Foreign Governments 982.1 — 29.8 121.2 890.7 Public Utilities 5,398.2 — 217.1 293.7 5,321.6 Mortgage/Asset-Backed Securities 658.0 — 10.1 24.0 644.1 All Other Corporate Bonds 26,708.4 2.2 771.8 1,807.3 25,670.7 Redeemable Preferred Stocks 4.0 — — 0.4 3.6 Total Fixed Maturity Securities $ 38,410.6 $ 2.2 $ 1,189.4 $ 2,763.9 $ 36,833.9 1 Allowance for Credit Losses
Schedule of Unrealized Loss on Investments	The following charts indicate the length of time our fixed maturity securities have been in a gross unrealized loss position. September 30, 2024 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 27.4 $ 0.3 $ 211.4 $ 13.6 States, Municipalities, and Political Subdivisions 145.0 2.5 2,061.0 433.1 Foreign Governments 50.5 1.7 320.5 135.4 Public Utilities 243.6 7.4 1,651.5 241.5 Mortgage/Asset-Backed Securities 81.3 0.2 304.3 16.2 All Other Corporate Bonds 1,013.2 9.6 13,185.8 1,512.6 Redeemable Preferred Stocks — — 3.7 0.3 Total Fixed Maturity Securities $ 1,561.0 $ 21.7 $ 17,738.2 $ 2,352.7 December 31, 2023 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 118.8 $ 0.7 $ 197.3 $ 18.4 States, Municipalities, and Political Subdivisions 128.0 4.0 2,035.1 494.2 Foreign Governments 149.9 3.3 312.9 117.9 Public Utilities 373.7 10.4 1,720.6 283.3 Mortgage/Asset-Backed Securities 60.3 2.5 316.7 21.5 All Other Corporate Bonds 1,483.8 26.8 14,215.2 1,780.5 Redeemable Preferred Stocks — — 3.6 0.4 Total Fixed Maturity Securities $ 2,314.5 $ 47.7 $ 18,801.4 $ 2,716.2
Distribution of the Maturity Dates for Fixed Maturity Securities	The following is a distribution of the maturity dates for fixed maturity securities. The maturity dates have not been adjusted for possible calls or prepayments. September 30, 2024 Amortized Cost, Net of ACL 1 Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 1,289.6 $ 2.6 $ 342.0 $ 5.5 $ 944.7 Over 1 year through 5 years 8,125.2 180.7 3,864.2 126.9 4,314.8 Over 5 years through 10 years 8,550.0 387.0 4,462.2 442.7 4,032.1 Over 10 years 20,001.1 754.7 9,350.9 1,782.9 9,622.0 37,965.9 1,325.0 18,019.3 2,358.0 18,913.6 Mortgage/Asset-Backed Securities 853.8 13.2 465.0 16.4 385.6 Total Fixed Maturity Securities $ 38,819.7 $ 1,338.2 $ 18,484.3 $ 2,374.4 $ 19,299.2 December 31, 2023 Amortized Cost, Net of ACL 1 Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 935.0 $ 0.9 $ 140.8 $ 7.5 $ 787.6 Over 1 year through 5 years 7,594.4 128.2 2,685.7 179.0 4,857.9 Over 5 years through 10 years 9,430.3 372.1 4,100.0 610.8 5,091.6 Over 10 years 19,790.7 678.1 8,524.4 1,942.6 10,001.8 37,750.4 1,179.3 15,450.9 2,739.9 20,738.9 Mortgage/Asset-Backed Securities 658.0 10.1 267.1 24.0 377.0 Total Fixed Maturity Securities $ 38,408.4 $ 1,189.4 $ 15,718.0 $ 2,763.9 $ 21,115.9 1 Allowance for Credit Losses
Distribution by External Credit Rating for Fixed Maturity Securities	The following chart depicts an analysis of our fixed maturity security portfolio between investment-grade and below-investment-grade categories as of September 30, 2024: Gross Unrealized Loss Fair Value Gross Unrealized Gain Amount Percent of Total Gross Unrealized Loss (in millions of dollars) Investment-Grade $ 36,287.2 $ 1,308.2 $ 2,308.8 97.2 % Below-Investment-Grade 1,496.3 30.0 65.6 2.8 Total Fixed Maturity Securities $ 37,783.5 $ 1,338.2 $ 2,374.4 100.0 %
Debt Securities, Available-for-sale, Allowance for Credit Loss	The following tables present a rollforward of the allowance for credit losses on available-for-sale fixed maturity securities, which were classified as "all other corporate bonds" during the three and nine months ended September 30, 2024. Three Months Ended September 30 2024 2023 (in millions of dollars) Balance, beginning of period $ 5.1 $ — Change in allowance on securities with allowance recorded in previous period 0.2 — Change in allowance on securities sold during the period (2.4) — Balance, end of period $ 2.9 $ — Nine Months Ended September 30 2024 2023 (in millions of dollars) Balance, beginning of period $ 2.2 $ — Credit losses on securities for which credit losses were not previously recorded 2.9 — Change in allowance on securities with allowance recorded in previous period 0.2 — Change in allowance on securities sold during the period (2.4) — Balance, end of period $ 2.9 $ —
Mortgage Loans by Property Type and Geographic Region	The carrying amount of mortgage loans by property type and geographic region are presented below. September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Amount Percent of Total Carrying Amount Percent of Total Property Type Apartment $ 662.9 29.6 % $ 685.8 29.6 % Industrial 684.2 30.6 706.0 30.5 Office 354.1 15.8 379.9 16.4 Retail 496.1 22.1 503.9 21.7 Other 41.6 1.9 42.6 1.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % Region New England $ 53.2 2.4 % $ 55.1 2.4 % Mid-Atlantic 162.4 7.3 155.1 6.7 East North Central 294.0 13.1 314.4 13.6 West North Central 158.9 7.1 163.5 7.0 South Atlantic 537.1 24.0 553.0 23.8 East South Central 107.8 4.8 110.7 4.8 West South Central 195.5 8.7 200.9 8.7 Mountain 269.5 12.0 282.7 12.2 Pacific 460.5 20.6 482.8 20.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 %
Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value	The following tables present information about mortgage loans by the applicable internal quality indicators: September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Amount Percent of Total Carrying Amount Percent of Total Internal Mortgage Rating AA $ 94.5 4.2 % $ 85.2 3.7 % A 982.2 43.9 942.5 40.6 BBB 1,064.4 47.5 1,249.5 53.9 BB 97.8 4.4 41.0 1.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % Loan-to-Value Ratio 1 <= 65% $ 1,527.0 68.2 % $ 1,409.9 60.8 % > 65% <= 75% 481.6 21.5 707.0 30.5 > 75% <= 85% 148.5 6.6 136.5 5.9 > 85% 81.8 3.7 64.8 2.8 Total $ 2,238.9 100.0 % $ 2,318.2 100.0 % 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property
Mortgage Loans by Credit Quality Indicators	The following tables present the amortized cost of our mortgage loans by year of origination and internal quality indicators at September 30, 2024 and December 31, 2023, respectively: September 30, 2024 Prior to 2020 2020 2021 2022 2023 2024 Total (in millions of dollars) Internal Mortgage Rating AA $ 88.1 $ — $ 6.4 $ — $ — $ — $ 94.5 A 684.4 92.6 145.0 24.3 38.0 — 984.3 BBB 710.4 63.1 181.1 63.8 29.0 23.1 1,070.5 BB 106.1 — — — — — 106.1 Total Amortized Cost 1,589.0 155.7 332.5 88.1 67.0 23.1 2,255.4 Allowance for credit losses (14.1) (0.5) (1.1) (0.3) (0.4) (0.1) (16.5) Carrying Amount $ 1,574.9 $ 155.2 $ 331.4 $ 87.8 $ 66.6 $ 23.0 $ 2,238.9 Loan-to-Value Ratio 1 <=65% $ 1,174.1 $ 113.7 $ 188.8 $ 15.6 $ 38.7 $ — $ 1,530.9 >65<=75% 231.2 33.9 94.9 72.5 28.3 23.1 483.9 >75%<=85% 122.6 8.1 20.3 — — — 151.0 >85% 61.1 — 28.5 — — — 89.6 Total Amortized Cost 1,589.0 155.7 332.5 88.1 67.0 23.1 2,255.4 Allowance for credit losses (14.1) (0.5) (1.1) (0.3) (0.4) (0.1) (16.5) Carrying Amount $ 1,574.9 $ 155.2 $ 331.4 $ 87.8 $ 66.6 $ 23.0 $ 2,238.9 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property December 31, 2023 Prior to 2019 2019 2020 2021 2022 2023 Total (in millions of dollars) Internal Mortgage Rating AA $ 74.3 $ 11.0 $ — $ — $ — $ — $ 85.3 A 589.0 100.3 94.1 100.1 23.2 38.0 944.7 BBB 618.4 224.8 71.4 248.0 64.4 29.2 1,256.2 BB 42.2 — — — — — 42.2 Total Amortized Cost 1,323.9 336.1 165.5 348.1 87.6 67.2 2,328.4 Allowance for credit losses (6.3) (1.3) (0.6) (1.0) (0.6) (0.4) (10.2) Carrying Amount $ 1,317.6 $ 334.8 $ 164.9 $ 347.1 $ 87.0 $ 66.8 $ 2,318.2 Loan-to-Value Ratio 1 <=65% $ 908.3 $ 197.7 $ 116.4 $ 145.2 $ 16.2 $ 30.0 $ 1,413.8 >65<=75% 252.1 138.4 40.8 171.0 71.4 37.2 710.9 >75%<=85% 97.3 — 8.3 31.9 — — 137.5 >85% 66.2 — — — — — 66.2 Total Amortized Cost 1,323.9 336.1 165.5 348.1 87.6 67.2 2,328.4 Allowance for credit losses (6.3) (1.3) (0.6) (1.0) (0.6) (0.4) (10.2) Carrying Amount $ 1,317.6 $ 334.8 $ 164.9 $ 347.1 $ 87.0 $ 66.8 $ 2,318.2 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property
Financing Receivable, Allowance for Credit Loss	The following tables present a roll-forward of the allowance for expected credit losses by loan-to-value ratio for the three and nine months ended September 30, 2024 and 2023 : Three Months Ended September 30, 2024 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.7 $ 0.3 $ — $ — $ 4.0 >65<=75% 3.3 (1.1) — — 2.2 >75%<=85% 1.7 0.8 — — 2.5 >85% 3.4 4.4 — — 7.8 Total $ 12.1 $ 4.4 $ — $ — $ 16.5 Three Months Ended September 30, 2023 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.3 $ (0.1) $ — $ — $ 3.2 >65<=75% 4.8 (0.4) — — 4.4 >75%<=85% 0.9 — — — 0.9 >85% 2.1 (0.4) — — 1.7 Total $ 11.1 $ (0.9) $ — $ — $ 10.2 Nine Months Ended September 30, 2024 Beginning of Year Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.8 $ 0.2 $ — $ — $ 4.0 >65<=75% 3.8 (1.6) — — 2.2 >75%<=85% 1.2 1.3 — — 2.5 >85% 1.4 6.4 — — 7.8 Total $ 10.2 $ 6.3 $ — $ — $ 16.5 Nine Months Ended September 30, 2023 Beginning of Year Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio 1 <=65% $ 3.0 $ 0.2 $ — $ — $ 3.2 >65<=75% 4.7 (0.3) — — 4.4 >75%<=85% 1.1 (0.2) — — 0.9 >85% 0.5 1.2 — — 1.7 Total $ 9.3 $ 0.9 $ — $ — $ 10.2 1 Loan-to-Value Ratio utilizes the most recent internal valuation of the property
Remaining Contractual Maturity of Securities Lending Agreements	The remaining contractual maturities of our securities lending agreements disaggregated by class of collateral pledged are as follows: September 30, 2024 December 31, 2023 Overnight and Continuous (in millions of dollars) Borrowings Public Utilities $ 3.7 $ 1.8 All Other Corporate Bonds 22.1 61.3 Total Borrowings 25.8 63.1 Gross Amount of Recognized Liability for Securities Lending Transactions 25.8 63.1 Amounts Related to Agreements Not Included in Offsetting Disclosure Contained Herein $ — $ —
Federal Home Loan Bank Common Stock Carrying Amounts, Amounts Posted, and Advances Received	The carrying value of common stock owned, collateral posted, and advances received are as follows: September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Value of FHLB Common Stock $ 25.6 $ 15.7 Advances from FHLB 299.0 64.5 Carrying Value of Collateral Posted to FHLB Fixed Maturity Securities $ 600.7 $ 589.0 Commercial Mortgage Loans 940.6 986.8 Total Carrying Value of Collateral Posted to FHLB $ 1,541.3 $ 1,575.8
Schedule of Financial Instrument and Derivative Offsetting	Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties. September 30, 2024 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 105.5 $ — $ 105.5 $ (102.9) $ (2.3) $ 0.3 Securities Lending 57.9 — 57.9 (32.1) (25.8) — Total $ 163.4 $ — $ 163.4 $ (135.0) $ (28.1) $ 0.3 Financial Liabilities: Derivatives $ 130.2 $ — $ 130.2 $ (127.7) $ — $ 2.5 Securities Lending 25.8 — 25.8 (25.8) — — Total $ 156.0 $ — $ 156.0 $ (153.5) $ — $ 2.5 December 31, 2023 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 99.9 $ — $ 99.9 $ (91.9) $ (6.4) $ 1.6 Securities Lending 72.0 — 72.0 (8.9) (63.1) — Total $ 171.9 $ — $ 171.9 $ (100.8) $ (69.5) $ 1.6 Financial Liabilities: Derivatives $ 116.2 $ — $ 116.2 $ (109.4) $ — $ 6.8 Securities Lending 63.1 — 63.1 (63.1) — — Total $ 179.3 $ — $ 179.3 $ (172.5) $ — $ 6.8
Net Investment Income	Net investment income reported in our consolidated statements of income is presented below. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Fixed Maturity Securities $ 465.4 $ 457.9 $ 1,388.5 $ 1,383.7 Derivatives 8.1 11.6 25.0 34.5 Mortgage Loans 22.0 22.9 66.6 69.8 Policy Loans 5.7 5.4 16.3 15.6 Other Long-term Investments Perpetual Preferred Securities 1 — 0.4 0.3 2.2 Private Equity Partnerships 2 19.6 22.6 72.6 56.7 Other 3.4 2.6 8.5 7.1 Short-term Investments 24.0 19.1 65.7 49.4 Gross Investment Income 548.2 542.5 1,643.5 1,619.0 Less Investment Expenses 17.5 13.5 48.3 44.0 Less Investment Income on Participation Fund Account Assets 2.9 3.0 8.8 9.1 Net Investment Income $ 527.8 $ 526.0 $ 1,586.4 $ 1,565.9 1 The net unrealized gain (loss) recognized in net investment income for the three months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was $0.2 million. The net unrealized gain (loss) recognized in net investment income for the nine months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was de minimis. The net unrealized gain (loss) recognized in net investment income for the three and nine months ended September 30, 2023 related to perpetual preferred securities still held at September 30, 2023 was $(0.4) million and $0.1 million, respectively. 2 The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2024 related to private equity partnerships still held at September 30, 2024 was $25.3 million and $87.6 million, respectively, reduced by net management fees and partnership expenses of $(5.7) million and $(15.0) million, respectively. The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2023 related to private equity partnerships still held at September 30, 2023 was $29.7 million and $72.6 million, respectively, reduced by net management fees and partnership expenses of $(7.1) million and $(15.9) million, respectively. See Note 3 for further discussion of private equity partnerships.
Investment Gains and Losses Reported in Consolidated Statements of Income	Investment gains and losses are as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Fixed Maturity Securities Gross Gains on Sales $ 1.1 $ 0.4 $ 1.1 $ 3.7 Gross Losses on Sales (8.5) (37.4) (29.7) (50.7) Impairment Loss 1 (1.3) — (2.5) — Change in Allowance for Credit Losses (0.2) — (3.1) — Mortgage Loans and Other Invested Assets Gross Gains on Sales 0.4 — 9.7 6.0 Gross Losses on Sales — (0.9) — (1.0) Impairment Loss — (3.0) — (3.0) Change in Allowance for Credit Losses (4.5) 0.9 (6.4) (0.9) Embedded Derivative in Modified Coinsurance Arrangement (0.8) 9.2 6.1 14.7 All Other Derivatives (2.2) 2.0 (0.2) 2.0 Foreign Currency Transactions 3.1 (2.2) 0.5 (0.8) Net Investment Gain (Loss) $ (12.9) $ (31.0) $ (24.5) $ (30.0) 1 Includes write-down of securities that we intend to sell prior to recovery of the amortized cost basis.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Nature and Amount of Collateral Received From and Posted To Derivative Counterparty	The table below summarizes the nature and amount of collateral received from and posted to our derivative counterparties. September 30, 2024 December 31, 2023 (in millions of dollars) Carrying Value of Collateral Received from Counterparties Cash $ 3.4 $ 11.1 Fixed Maturity Securities 30.9 26.3 $ 34.3 $ 37.4 Carrying Value of Collateral Posted to Counterparties Cash $ — $ — Fixed Maturity Securities 50.6 39.8 $ 50.6 $ 39.8
Fair Value Hedges Carrying Amount of Hedged Assets and Liabilities and Cumulative Basis Adjustments	The following table summarizes the carrying amount of hedged assets and the related cumulative basis adjustments related to our fair value hedges: Carrying Amount of Hedged Assets Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets September 30, 2024 December 31, 2023 September 30, 2024 December 31, 2023 (in millions of dollars) Fixed maturity securities: Receive fixed functional currency interest, pay fixed foreign currency interest $ 592.9 $ 529.2 $ (0.5) $ (6.1)
Location and Fair Values of Derivative Financial Instruments	The following tables summarize the notional amounts and fair values of derivative financial instruments, as reported in our consolidated balance sheets. Derivative assets are included in other long-term investments, while derivative liabilities are included in other liabilities within our consolidated balance sheets. The notional amounts represent the basis upon which our counterparty pay and receive amounts are calculated. September 30, 2024 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Forward Benchmark Interest Rate Locks $ 2,523.0 $ 47.4 $ 94.7 Foreign Currency Interest Rate Swaps 142.5 14.9 3.0 Total Cash Flow Hedges 2,665.5 62.3 97.7 Fair Value Hedges Foreign Currency Interest Rate Swaps 693.2 41.1 15.7 Total Designated as Hedging Instruments $ 3,358.7 $ 103.4 $ 113.4 Not Designated as Hedging Instruments Foreign Currency Forwards $ 54.6 $ 2.1 $ 0.5 Foreign Currency Interest Rate Swaps 125.9 — 16.3 Total Return Swaps 126.3 — — Embedded Derivative in Modified Coinsurance Arrangement — 4.6 — Total Not Designated as Hedging Instruments $ 306.8 $ 6.7 $ 16.8 Total Derivatives $ 3,665.5 $ 110.1 $ 130.2 December 31, 2023 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Forward Benchmark Interest Rate Locks $ 1,905.0 $ 44.5 $ 77.8 Foreign Currency Interest Rate Swaps 149.5 14.2 4.5 Total Cash Flow Hedges 2,054.5 58.7 82.3 Fair Value Hedges Foreign Currency Interest Rate Swaps 642.5 38.2 16.7 Total Designated as Hedging Instruments $ 2,697.0 $ 96.9 $ 99.0 Not Designated as Hedging Instruments Foreign Currency Forwards $ 52.5 $ 3.0 $ 0.2 Foreign Currency Interest Rate Swaps 132.0 — 17.0 Total Return Swaps 102.2 — — Embedded Derivative in Modified Coinsurance Arrangement — — 1.5 Total Not Designated as Hedging Instruments $ 286.7 $ 3.0 $ 18.7 Total Derivatives $ 2,983.7 $ 99.9 $ 117.7
Location of Gains and Losses on Derivative Instruments Designated as Cash Flow Hedging Instruments	The following tables summarize the location of gains and losses of derivative financial instruments designated as hedging instruments, as reported in our consolidated statements of income. Three Months Ended September 30 2024 2023 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 527.8 $ (12.9) $ 49.2 $ 526.0 $ (31.0) $ 48.6 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged Items 21.1 — 0.7 49.7 — 0.7 Derivatives Designated as Hedging Instruments 3.7 — — 8.3 — — Foreign Exchange Contracts: Hedged Items 2.3 (0.7) — 2.3 (0.1) — Derivatives Designated as Hedging Instruments 0.9 0.7 — 0.4 — — Forward Benchmark Interest Rate Locks: Hedged Items 10.7 — — 3.9 — — Derivatives Designated as Hedging Instruments (0.3) — — (0.1) — — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged Items 4.9 25.2 — 3.9 (15.2) — Derivatives Designated as Hedging Instruments 4.2 (25.2) — 3.1 15.2 — Nine Months Ended September 30 2024 2023 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 1,586.4 $ (24.5) $ 148.6 $ 1,565.9 $ (30.0) $ 145.6 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged Items 91.3 — 2.2 148.2 0.8 2.2 Derivatives Designated as Hedging Instruments 14.5 — — 27.7 — — Foreign Exchange Contracts: Hedged Items 6.5 (0.4) — 7.3 (0.1) — Derivatives Designated as Hedging Instruments 0.5 0.5 — 0.6 0.1 — Forward Benchmark Interest Rate Locks: Hedged Items 29.6 — — 7.7 — — Derivatives Designated as Hedging Instruments (0.7) — — (0.1) — — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged Items 13.4 5.6 — 10.3 (8.7) — Derivatives Designated as Hedging Instruments 11.5 (5.6) — 6.7 8.7 —
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the location of gains and losses of derivative financial instruments designated as cash flow hedging instruments, as reported in our consolidated statements of comprehensive income (loss). Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Gain (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives Forwards $ 66.0 $ (158.9) $ (39.6) $ (159.7) Foreign Exchange Contracts (1.2) 3.4 2.6 0.7 Total $ 64.8 $ (155.5) $ (37.0) $ (159.0)
Gains and Losses on Derivatives Not Designated as Hedging Instruments	The following table summarizes the location of gains and losses on our derivatives not designated as hedging instruments, as reported in our consolidated statements of income. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Net Investment Gain (Loss) Foreign Exchange Contracts $ (2.2) $ 2.0 $ (0.2) $ 2.0 Embedded Derivative in Modified Coinsurance Arrangement (0.8) 9.2 6.1 14.7 Total $ (3.0) $ 11.2 $ 5.9 $ 16.7 Other Expenses (Gain) Loss on Total Return Swaps $ (5.4) $ 4.1 $ (14.1) $ (4.7)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Components of our accumulated other comprehensive loss, after tax, and related changes are as follows: Net Unrealized Loss on Securities Effect of Change in Discount Rate Assumptions on the LFPB 1 Net Loss on Derivatives Foreign Currency Translation Adjustment Unrecognized Pension and Postretirement Benefit Costs Total (in millions of dollars) Balance at June 30, 2024 $ (2,723.8) $ 712.3 $ (164.6) $ (328.4) $ (341.7) $ (2,846.2) Other Comprehensive Income (Loss) Before Reclassifications 1,225.8 (1,239.3) 58.8 68.5 (4.2) 109.6 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 6.8 — (3.1) — 3.2 6.9 Net Other Comprehensive Income (Loss) 1,232.6 (1,239.3) 55.7 68.5 (1.0) 116.5 Balance at September 30, 2024 $ (1,491.2) $ (527.0) $ (108.9) $ (259.9) $ (342.7) $ (2,729.7) Balance at June 30, 2023 $ (2,762.6) $ 0.1 $ (33.3) $ (327.1) $ (334.7) $ (3,457.6) Other Comprehensive Income (Loss) Before Reclassifications (1,215.1) 1,688.4 (137.9) (55.1) 2.5 282.8 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 29.3 — (6.5) — 1.4 24.2 Net Other Comprehensive Income (Loss) (1,185.8) 1,688.4 (144.4) (55.1) 3.9 307.0 Balance at September 30, 2023 $ (3,948.4) $ 1,688.5 $ (177.7) $ (382.2) $ (330.8) $ (3,150.6) Balance at December 31, 2023 $ (1,919.1) $ (648.4) $ (73.7) $ (321.1) $ (345.7) $ (3,308.0) Other Comprehensive Income (Loss) Before Reclassifications 401.1 121.4 (24.3) 61.2 (6.6) 552.8 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 26.8 — (10.9) — 9.6 25.5 Net Other Comprehensive Income (Loss) 427.9 121.4 (35.2) 61.2 3.0 578.3 Balance at September 30, 2024 $ (1,491.2) $ (527.0) $ (108.9) $ (259.9) $ (342.7) $ (2,729.7) Balance at December 31, 2022 $ (3,028.4) $ 313.9 $ (9.6) $ (390.1) $ (334.1) $ (3,448.3) Other Comprehensive Income (Loss) Before Reclassifications (957.2) 1,374.6 (146.4) 7.9 (0.9) 278.0 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 37.2 — (21.7) — 4.2 19.7 Net Other Comprehensive Income (Loss) (920.0) 1,374.6 (168.1) 7.9 3.3 297.7 Balance at September 30, 2023 $ (3,948.4) $ 1,688.5 $ (177.7) $ (382.2) $ (330.8) $ (3,150.6) 1 Liability for Future Policy Benefits
Schedule of Reclassification out of Accumulated Other Comprehensive Income (Loss)	Amounts reclassified from accumulated other comprehensive loss were recognized in our consolidated statements of income as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Net Unrealized Loss on Securities Net Investment Loss on Fixed Maturity Securities Net Loss on Sales $ (7.4) $ (37.0) $ (28.6) $ (47.0) Impairment Loss (1.3) — (2.5) — Change in Allowance for Credit Losses (0.2) — (3.1) — (8.9) (37.0) (34.2) (47.0) Income Tax Benefit (2.1) (7.7) (7.4) (9.8) Total $ (6.8) $ (29.3) $ (26.8) $ (37.2) Net Loss on Derivatives Net Investment Income Gain on Interest Rate Swaps and Forwards $ 3.4 $ 8.3 $ 13.8 $ 27.6 Loss on Foreign Currency Interest Rate Swaps — (0.1) (0.1) (0.2) Net Investment Gain Gain on Foreign Currency Interest Rate Swaps 0.6 — 0.1 0.1 4.0 8.2 13.8 27.5 Income Tax Expense 0.9 1.7 2.9 5.8 Total $ 3.1 $ 6.5 $ 10.9 $ 21.7 Unrecognized Pension and Postretirement Benefit Costs Other Expenses Amortization of Net Actuarial Loss $ (4.2) $ (1.8) $ (12.4) $ (5.4) Amortization of Prior Service Credit 0.1 — 0.2 0.1 (4.1) (1.8) (12.2) (5.3) Income Tax Benefit (0.9) (0.4) (2.6) (1.1) Total $ (3.2) $ (1.4) $ (9.6) $ (4.2)

Liability for Future Policy B_2

Liability for Future Policy Benefits, Policyholder's Account Balances, and Deferred Acquisition Costs (Tables)	9 Months Ended
	Sep. 30, 2024
Insurance [Abstract]
Liability for Future Policy Benefit, Activity	The following table presents balances as well as the changes in the liability for future policy benefits for traditional long duration products. Consolidated September 30 2024 2023 (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 14,417.8 $ 12,426.2 Beginning balance at original discount rate 14,243.2 12,695.3 Effect of changes in cash flow assumptions 73.0 1,499.2 Effect of actual variances from expected experience (151.9) (121.8) Adjusted beginning of year balance 14,164.3 14,072.7 Issuances 856.7 861.2 Interest accretion 481.8 430.8 Net premiums collected (1,222.6) (1,164.9) Foreign currency 7.3 (0.1) Ending balance at original discount rate 14,287.5 14,199.7 Effect of change in discount rate assumptions 319.0 (709.0) Balance, end of period $ 14,606.5 $ 13,490.7 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 52,423.6 $ 48,929.4 Beginning balance at original discount rate 51,305.7 49,689.0 Effect of changes in cash flow assumptions (248.5) 1,702.0 Effect of actual variances from expected experience (355.6) (356.4) Adjusted beginning of year balance 50,701.6 51,034.6 Issuances 1 2,506.9 2,547.0 Interest accretion 1,707.3 1,670.3 Benefit payments (4,078.4) (4,106.1) Foreign currency 121.0 19.6 Ending balance at original discount rate 50,958.4 51,165.4 Effect of change in discount rate assumptions 1,204.1 (3,111.7) Balance, end of period $ 52,162.5 $ 48,053.7 Net liability for future policy benefits $ 37,556.0 $ 34,563.0 Other 2 1,655.7 1,703.3 Total liability for future policy benefits 39,211.7 36,266.3 Less: Reinsurance recoverable related to future policy benefits 7,455.9 7,449.0 Net liability for future policy benefits, after reinsurance recoverable $ 31,755.8 $ 28,817.3 1 Issuances include new policy issuances for most product lines. For our Unum US group disability, Unum US group life and AD&D and Closed Block - All Other product lines and certain of our Unum International product lines, this line represents new claim incurrals. 2 Other primarily relates to our Closed Block - All Other product line. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products presented in the rollforward activity above. Consolidated Nine Months Ended September 30 2024 2023 (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 7,568.4 $ 7,278.4 Interest accretion $ 1,225.5 $ 1,239.5 Consolidated September 30 2024 2023 (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 104,039.1 $ 105,306.1 Expected future gross premiums $ 39,394.1 $ 38,581.4 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 25,941.4 $ 25,435.2 Weighted average interest rate: Interest accretion rate 4.9 % 4.8 % Current discount rate 4.8 % 5.6 % Weighted average duration of the liability 11.5 years 11.5 years The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Unum US segment. September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ — $ — $ 1,134.7 $ 1,296.7 $ 2,431.4 Beginning balance at original discount rate — — 1,192.5 1,294.4 2,486.9 Effect of changes in cash flow assumptions — — 41.5 (100.2) (58.7) Effect of actual variances from expected experience — — (72.1) (5.3) (77.4) Adjusted beginning of year balance — — 1,161.9 1,188.9 2,350.8 Issuances 1 — — 295.0 119.2 414.2 Interest accretion — — 29.9 39.8 69.7 Net premiums collected — — (144.9) (138.7) (283.6) Ending balance at original discount rate — — 1,341.9 1,209.2 2,551.1 Effect of change in discount rate assumptions — — (41.7) 16.7 (25.0) Balance, end of period $ — $ — $ 1,300.2 $ 1,225.9 $ 2,526.1 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 5,147.4 $ 922.0 $ 2,334.5 $ 3,348.6 $ 11,752.5 Beginning balance at original discount rate 5,277.1 936.5 2,422.0 3,313.9 11,949.5 Effect of changes in cash flow assumptions (76.4) (17.0) 51.6 (155.4) (197.2) Effect of actual variances from expected experience (152.4) (49.7) (81.1) (18.9) (302.1) Adjusted beginning of year balance 5,048.3 869.8 2,392.5 3,139.6 11,450.2 Issuances 1 893.7 333.3 315.1 127.1 1,669.2 Interest accretion 121.7 14.3 73.2 113.3 322.5 Benefit payments (1,109.7) (357.8) (170.3) (207.2) (1,845.0) Ending balance at original discount rate 4,954.0 859.6 2,610.5 3,172.8 11,596.9 Effect of change in discount rate assumptions (43.4) (6.3) (91.7) 65.8 (75.6) Balance, end of period $ 4,910.6 $ 853.3 $ 2,518.8 $ 3,238.6 $ 11,521.3 Net liability for future policy benefits $ 4,910.6 $ 853.3 $ 1,218.6 $ 2,012.7 $ 8,995.2 Other 0.1 0.8 2.7 28.1 31.7 Total liability for future policy benefits 4,910.7 854.1 1,221.3 2,040.8 9,026.9 Less: Reinsurance recoverable related to future policy benefits 26.8 5.7 13.7 154.6 200.8 Net liability for future policy benefits, after reinsurance recoverable $ 4,883.9 $ 848.4 $ 1,207.6 $ 1,886.2 $ 8,826.1 1 Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals. September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ — $ — $ 868.2 $ 1,202.9 $ 2,071.1 Beginning balance at original discount rate — — 937.9 1,228.1 2,166.0 Effect of changes in cash flow assumptions — — 180.7 5.0 185.7 Effect of actual variances from expected experience — — (98.2) (13.6) (111.8) Adjusted beginning of year balance — — 1,020.4 1,219.5 2,239.9 Issuances 1 — — 258.6 164.0 422.6 Interest accretion — — 21.4 36.3 57.7 Net premiums collected — — (124.2) (131.7) (255.9) Ending balance at original discount rate — — 1,176.2 1,288.1 2,464.3 Effect of change in discount rate assumptions — — (119.4) (62.2) (181.6) Balance, end of period $ — $ — $ 1,056.8 $ 1,225.9 $ 2,282.7 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 5,533.3 $ 972.6 $ 1,999.5 $ 3,192.8 $ 11,698.2 Beginning balance at original discount rate 5,793.1 998.5 2,141.2 3,244.5 12,177.3 Effect of changes in cash flow assumptions (100.2) — 170.1 7.9 77.8 Effect of actual variances from expected experience (187.8) (28.2) (109.6) (42.3) (367.9) Adjusted beginning of year balance 5,505.1 970.3 2,201.7 3,210.1 11,887.2 Issuances 1 907.1 356.1 270.4 173.8 1,707.4 Interest accretion 137.6 15.8 64.3 123.2 340.9 Benefit payments (1,186.8) (402.1) (143.9) (203.5) (1,936.3) Ending balance at original discount rate 5,363.0 940.1 2,392.5 3,303.6 11,999.2 Effect of change in discount rate assumptions (310.1) (35.6) (280.7) (190.0) (816.4) Balance, end of period $ 5,052.9 $ 904.5 $ 2,111.8 $ 3,113.6 $ 11,182.8 Net liability for future policy benefits $ 5,052.9 $ 904.5 $ 1,055.0 $ 1,887.7 $ 8,900.1 Other 0.5 1.0 2.4 26.0 29.9 Total liability for future policy benefits 5,053.4 905.5 1,057.4 1,913.7 8,930.0 Less: Reinsurance recoverable related to future policy benefits 32.8 6.2 13.2 148.1 200.3 Net liability for future policy benefits, after reinsurance recoverable $ 5,020.6 $ 899.3 $ 1,044.2 $ 1,765.6 $ 8,729.7 1 Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Unum US segment presented in the rollforward activity above. Nine Months Ended September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 2,294.8 $ 1,496.3 $ 621.3 $ 494.2 $ 4,906.6 Interest accretion $ 121.7 $ 14.3 $ 43.3 $ 73.5 $ 252.8 Nine Months Ended September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 2,210.4 $ 1,403.2 $ 592.1 $ 474.2 $ 4,679.9 Interest accretion $ 137.6 $ 15.8 $ 42.9 $ 86.9 $ 283.2 September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 6,001.5 $ 977.0 $ 5,579.6 $ 5,082.2 $ 17,640.3 Expected future gross premiums $ — $ — $ 5,822.4 $ 5,817.0 $ 11,639.4 Amount of discounted (at interest accretion rate): Expected future gross premiums $ — $ — $ 3,854.6 $ 4,180.2 $ 8,034.8 Weighted average interest rate: Interest accretion rate 4.1 % 2.3 % 5.0 % 5.1 % 4.3 % Current discount rate 4.3 % 2.4 % 4.9 % 4.6 % 4.3 % Weighted average duration of the liability 4.2 years 2.5 years 18.5 years 9.4 years 7.1 years September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Total Unum US (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 6,474.2 $ 1,069.2 $ 5,107.4 $ 5,292.7 $ 17,943.5 Expected future gross premiums $ — $ — $ 5,317.5 $ 5,701.8 $ 11,019.3 Amount of discounted (at interest accretion rate): Expected future gross premiums $ — $ — $ 3,663.8 $ 4,099.5 $ 7,763.3 Weighted average interest rate: Interest accretion rate 4.0 % 2.3 % 5.0 % 5.1 % 4.2% Current discount rate 5.4 % 3.1 % 5.7 % 5.7 % 5.3% Weighted average duration of the liability 4.3 years 2.7 years 18.2 years 9.6 years 6.9 years The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Unum International segment. September 30 2024 2023 (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 270.3 $ 197.1 Beginning balance at original discount rate 298.4 246.8 Effect of changes in cash flow assumptions (5.9) (5.1) Effect of actual variances from expected experience 15.1 12.2 Adjusted beginning of year balance 307.6 253.9 Issuances 1 25.3 16.9 Interest accretion 8.7 6.9 Net premiums collected (21.2) (16.9) Foreign currency 7.3 (0.1) Ending balance at original discount rate 327.7 260.7 Effect of change in discount rate assumptions (27.9) (37.6) Balance, end of period $ 299.8 $ 223.1 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 2,527.4 $ 2,231.4 Beginning balance at original discount rate 2,687.1 2,495.5 Effect of changes in cash flow assumptions 0.1 17.7 Effect of actual variances from expected experience (13.4) (9.2) Adjusted beginning of year balance 2,673.8 2,504.0 Issuances 1 300.3 277.3 Interest accretion 51.3 47.7 Benefit payments (326.4) (307.5) Foreign currency 121.0 19.6 Ending balance at original discount rate 2,820.0 2,541.1 Effect of change in discount rate assumptions (214.9) (297.1) Balance, end of period $ 2,605.1 $ 2,244.0 Net liability for future policy benefits $ 2,305.3 $ 2,020.9 Other 43.1 30.3 Total liability for future policy benefits 2,348.4 2,051.2 Less: Reinsurance recoverable related to future policy benefits 78.0 69.4 Net liability for future policy benefits, after reinsurance recoverable $ 2,270.4 $ 1,981.8 1 Issuances for Unum International primarily represent new claim incurrals. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Unum International segment presented in the rollforward activity above. Nine Months Ended September 30 2024 2023 (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 710.2 $ 667.7 Interest accretion $ 42.6 $ 40.8 September 30 2024 2023 (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 4,536.2 $ 4,012.8 Expected future gross premiums $ 1,335.6 $ 1,035.7 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 854.1 $ 676.8 Weighted average interest rate: Interest accretion rate 4.1 % 4.0 % Current discount rate 4.9 % 5.4 % Weighted average duration of the liability 8.9 years 8.6 years The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Colonial Life segment. September 30 2024 2023 (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 3,592.6 $ 3,745.4 Beginning balance at original discount rate 3,754.3 4,046.4 Effect of changes in cash flow assumptions (7.9) (322.7) Effect of actual variances from expected experience (57.0) (77.1) Adjusted beginning of year balance 3,689.4 3,646.6 Issuances 417.2 421.7 Interest accretion 101.4 94.3 Net premiums collected (455.5) (454.0) Ending balance at original discount rate 3,752.5 3,708.6 Effect of change in discount rate assumptions (105.6) (348.7) Balance, end of period $ 3,646.9 $ 3,359.9 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 5,566.0 $ 5,581.1 Beginning balance at original discount rate 5,925.2 6,163.9 Effect of changes in cash flow assumptions (52.7) (402.9) Effect of actual variances from expected experience (84.2) (90.1) Adjusted beginning of year balance 5,788.3 5,670.9 Issuances 455.1 461.1 Interest accretion 172.2 161.0 Benefit payments (458.4) (462.1) Ending balance at original discount rate 5,957.2 5,830.9 Effect of change in discount rate assumptions (303.5) (731.9) Balance, end of period $ 5,653.7 $ 5,099.0 Net liability for future policy benefits $ 2,006.8 $ 1,739.1 Other 25.1 24.3 Total liability for future policy benefits 2,031.9 1,763.4 Less: Reinsurance recoverable related to future policy benefits 1.5 0.9 Net liability for future policy benefits, after reinsurance recoverable $ 2,030.4 $ 1,762.5 The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Colonial Life segment presented in the rollforward activity above. Nine Months Ended September 30 2024 2023 (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 1,286.4 $ 1,240.3 Interest accretion $ 70.8 $ 66.7 September 30 2024 2023 (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 10,242.2 $ 9,568.2 Expected future gross premiums $ 12,450.4 $ 11,847.5 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 8,948.9 $ 8,684.1 Weighted average interest rate: Interest accretion rate 4.4 % 4.3 % Current discount rate 4.8 % 5.7 % Weighted average duration of the liability 17.3 years 16.9 years The following table presents the balances and changes in the reserves for future policy benefits for traditional long duration products in the Closed Block segment. September 30, 2024 Long-term Care All Other Total Closed Block (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 8,123.5 $ — $ 8,123.5 Beginning balance at original discount rate 7,703.6 — 7,703.6 Effect of changes in cash flow assumptions 145.5 — 145.5 Effect of actual variances from expected experience (32.6) — (32.6) Adjusted beginning of year balance 7,816.5 — 7,816.5 Interest accretion 302.0 — 302.0 Net premiums collected (462.3) — (462.3) Ending balance at original discount rate 7,656.2 — 7,656.2 Effect of change in discount rate assumptions 477.5 — 477.5 Balance, end of period $ 8,133.7 $ — $ 8,133.7 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 24,697.7 $ 7,880.0 $ 32,577.7 Beginning balance at original discount rate 22,649.3 8,094.6 30,743.9 Effect of changes in cash flow assumptions (4.1) 5.4 1.3 Effect of actual variances from expected experience 38.9 5.2 44.1 Adjusted beginning of year balance 22,684.1 8,105.2 30,789.3 Issuances 1 — 82.3 82.3 Interest accretion 899.7 261.6 1,161.3 Benefit payments (710.0) (738.6) (1,448.6) Ending balance at original discount rate 22,873.8 7,710.5 30,584.3 Effect of change in discount rate assumptions 1,927.3 (129.2) 1,798.1 Balance, end of period $ 24,801.1 $ 7,581.3 $ 32,382.4 Net liability for future policy benefits $ 16,667.4 $ 7,581.3 $ 24,248.7 Other 2 (0.7) 1,556.5 1,555.8 Total liability for future policy benefits 16,666.7 9,137.8 25,804.5 Less: Reinsurance recoverable related to future policy benefits 4.2 7,171.4 7,175.6 Net liability for future policy benefits, after reinsurance recoverable $ 16,662.5 $ 1,966.4 $ 18,628.9 1 Issuances for Closed Block - All Other represents new claim incurrals. 2 Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products. September 30, 2023 Long-term Care All Other Total Closed Block (in millions of dollars) Present Value of Expected Net Premiums Balance, beginning of year $ 6,412.6 $ — $ 6,412.6 Beginning balance at original discount rate 6,236.1 — 6,236.1 Effect of changes in cash flow assumptions 1,641.3 — 1,641.3 Effect of actual variances from expected experience 54.9 — 54.9 Adjusted beginning of year balance 7,932.3 — 7,932.3 Interest accretion 271.9 — 271.9 Net premiums collected (438.1) — (438.1) Ending balance at original discount rate 7,766.1 — 7,766.1 Effect of change in discount rate assumptions (141.1) — (141.1) Balance, end of period $ 7,625.0 $ — $ 7,625.0 Present Value of Expected Future Policy Benefits Balance, beginning of year $ 21,199.9 $ 8,218.8 $ 29,418.7 Beginning balance at original discount rate 20,221.6 8,630.7 28,852.3 Effect of changes in cash flow assumptions 2,009.4 — 2,009.4 Effect of actual variances from expected experience 106.7 4.1 110.8 Adjusted beginning of year balance 22,337.7 8,634.8 30,972.5 Issuances 1 — 101.2 101.2 Interest accretion 850.7 270.0 1,120.7 Benefit payments (624.2) (776.0) (1,400.2) Ending balance at original discount rate 22,564.2 8,230.0 30,794.2 Effect of change in discount rate assumptions (579.3) (687.0) (1,266.3) Balance, end of period $ 21,984.9 $ 7,543.0 $ 29,527.9 Net liability for future policy benefits $ 14,359.9 $ 7,543.0 $ 21,902.9 Other 2 12.8 1,606.0 1,618.8 Total liability for future policy benefits 14,372.7 9,149.0 23,521.7 Less: Reinsurance recoverable related to future policy benefits 4.6 7,173.7 7,178.3 Net liability for future policy benefits, after reinsurance recoverable $ 14,368.1 $ 1,975.3 $ 16,343.4 1 Issuances for Closed Block - All Other represents new claim incurrals. 2 Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products. The following tables summarize the amount of gross premiums and interest accretion reflected in the statements of income as well as the undiscounted and discounted expected gross premiums and expected future benefit payments and the weighted average interest rates for traditional long duration products in the Closed Block segment presented in the rollforward activity above. Nine Months Ended September 30, 2024 Long-term Care All Other Total Closed Block (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 521.6 $ 143.6 $ 665.2 Interest accretion $ 597.7 $ 261.6 $ 859.3 Nine Months Ended September 30, 2023 Long-term Care All Other Total Closed Block (in millions of dollars) Amount recognized in the statement of income: Gross premiums or assessments $ 521.2 $ 169.3 $ 690.5 Interest accretion $ 578.8 $ 270.0 $ 848.8 September 30, 2024 Long-term Care All Other Total Closed Block (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 60,339.0 $ 11,281.4 $ 71,620.4 Expected future gross premiums $ 13,968.7 $ — $ 13,968.7 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 8,103.6 $ — $ 8,103.6 Weighted average interest rate: Interest accretion rate 5.6 % 4.6 % 5.2 % Current discount rate 5.0 % 4.7 % 4.9 % Weighted average duration of the liability 15.9 years 7.2 years 13.0 years September 30, 2023 Long-term Care All Other Total Closed Block (in millions of dollars, except weighted average data) Amount of undiscounted: Expected future benefit payments $ 61,672.0 $ 12,109.6 $ 73,781.6 Expected future gross premiums $ 14,678.9 $ — $ 14,678.9 Amount of discounted (at interest accretion rate): Expected future gross premiums $ 8,311.0 $ — $ 8,311.0 Weighted average interest rate: Interest accretion rate 5.6 % 4.6 % 5.2% Current discount rate 5.8 % 5.7 % 5.8% Weighted average duration of the liability 16.6 years 7.3 years 13.3 years A reconciliation of the liability for future policy benefits reflected in the preceding rollforwards to the related liability balances in the consolidated balance sheets are as follows: September 30 2024 2023 (in millions of dollars) Liability for future policy benefits Unum US 1 $ 9,026.9 $ 8,930.0 Unum International 2,348.4 2,051.2 Colonial Life 2,031.9 1,763.4 Closed Block 1 25,804.5 23,521.7 Other products 1 232.8 236.1 Total liability for future policy benefits $ 39,444.5 $ 36,502.4 1
Policyholder Account Balance	The following table presents the balances and changes in the policyholders' account balances: September 30, 2024 Unum US - Voluntary Benefits Colonial Life Closed Block - All Other Total (in millions of dollars, except weighted average data) Balance, beginning of year $ 578.6 $ 852.9 $ 4,082.7 $ 5,514.2 Premiums received 40.7 60.2 23.3 124.2 Policy charges 1 (42.9) (54.2) (73.7) (170.8) Surrenders and withdrawals (24.3) (30.4) (9.8) (64.5) Benefit payments (4.8) (6.0) (157.1) (167.9) Interest credited 15.7 25.6 220.1 261.4 Other 7.6 0.2 0.8 8.6 Balance, end of period 570.6 848.3 4,086.3 5,505.2 Reserves in excess of account balance 104.4 14.5 37.2 156.1 Total policyholders' account balances 675.0 862.8 4,123.5 5,661.3 Less: Reinsurance recoverable related to policyholders' account balances 0.8 — 4,123.5 4,124.3 Net policyholders' account balances, after reinsurance recoverable $ 674.2 $ 862.8 $ — $ 1,537.0 Weighted average crediting rate 3.7% 4.1% 7.4% 6.5% Net amount at risk 2 $ 4,210.4 $ 8,325.0 $ 1,698.7 $ 14,234.1 Cash surrender value $ 560.4 $ 817.1 $ 4,062.7 $ 5,440.2 1 Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance. 2 For those guarantees of benefits that are payable in the event of death, the net amount at risk is generally defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date. September 30, 2023 Unum US - Voluntary Benefits Colonial Life Closed Block - All Other Total (in millions of dollars, except weighted average data) Balance, beginning of year $ 586.8 $ 852.4 $ 4,159.4 $ 5,598.6 Premiums received 44.9 64.4 25.2 134.5 Policy charges 1 (45.8) (56.3) (78.9) (181.0) Surrenders and withdrawals (23.6) (28.5) (12.1) (64.2) Benefit payments (7.5) (5.6) (191.0) (204.1) Interest credited 17.0 25.7 239.0 281.7 Other 6.7 (0.2) 24.3 30.8 Balance, end of period 578.5 851.9 4,165.9 5,596.3 Reserves in excess of account balance 99.2 16.6 32.4 148.2 Total policyholders' account balances 677.7 868.5 4,198.3 5,744.5 Less: Reinsurance recoverable related to policyholders' account balances 1.0 — 4,198.3 4,199.3 Net policyholders' account balances, after reinsurance recoverable $ 676.7 $ 868.5 $ — $ 1,545.2 Weighted average crediting rate 4.0% 4.1% 8.0% 6.9% Net amount at risk 2 $ 4,600.0 $ 8,901.6 $ 1,807.1 $ 15,308.7 Cash surrender value $ 568.9 $ 810.1 $ 4,033.4 $ 5,412.4 1 Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance. 2 For those guarantees of benefits that are payable in the event of death, the net amount at risk is generally defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date.
Policyholder Account Balance, Guaranteed Minimum Crediting Rate	The balance of the account values by range of guaranteed minimum crediting rates and the related range of difference, in basis points, between rates being credited to policyholders and the respective guaranteed minimums is as follows. September 30, 2024 Range of Guaranteed Minimum Crediting Rate At Guaranteed Minimum 1 Basis Point - 50 Basis Points Above 51 Basis Points - 150 Basis Points Above Greater than 150 Basis Points Above Total (in millions of dollars) Unum US - Voluntary Benefits 3.00% - 3.99% $ 89.8 $ — $ — $ — $ 89.8 4.00% - 4.99% 220.2 193.6 35.8 — 449.6 5.00% - 6.00% 31.2 — — — 31.2 341.2 193.6 35.8 — 570.6 Colonial Life 4.00% - 5.00% 842.0 6.3 — — 848.3 Closed Block - All Other 3.00% - 5.99% 415.9 1,117.1 27.7 — 1,560.7 6.00% - 8.99% 1.3 25.6 — — 26.9 9.00% - 11.99% — 2,299.3 — — 2,299.3 12.00% - 15.00% — 199.4 — — 199.4 417.2 3,641.4 27.7 — 4,086.3 Total $ 1,600.4 $ 3,841.3 $ 63.5 $ — $ 5,505.2 September 30, 2023 Range of Guaranteed Minimum Crediting Rate At Guaranteed Minimum 1 Basis Point - 50 Basis Points Above 51 Basis Points - 150 Basis Points Above Greater than 150 Basis Points Above Total (in millions of dollars) Unum US - Voluntary Benefits 3.00% - 3.99% $ 91.6 $ — $ — $ — $ 91.6 4.00% - 4.99% 265.4 188.5 — — 453.9 5.00% - 6.00% 33.0 — — — 33.0 390.0 188.5 — — 578.5 Colonial Life 4.00% - 5.00% 845.8 6.1 — — 851.9 Closed Block - All Other 3.00% - 5.99% 431.3 1,181.2 27.1 — 1,639.6 6.00% - 8.99% 2.1 28.5 — — 30.6 9.00% - 11.99% 398.4 1,914.7 — — 2,313.1 12.00% - 15.00% — 182.6 — — 182.6 831.8 3,307.0 27.1 — 4,165.9 Total $ 2,067.6 $ 3,501.6 $ 27.1 $ — $ 5,596.3
Deferred Policy Acquisition Costs	The following tables display the changes in DAC throughout the period: September 30, 2024 Unum US Unum International Colonial Life Total (in millions of dollars) Balance, beginning of year $ 1,232.2 $ 46.9 $ 1,435.4 $ 2,714.5 Capitalization 247.4 13.2 234.7 495.3 Amortization expense (216.7) (7.3) (163.9) (387.9) Foreign currency — 1.6 — 1.6 Balance, end of period $ 1,262.9 $ 54.4 $ 1,506.2 $ 2,823.5 September 30, 2023 Unum US Unum International Colonial Life Total (in millions of dollars) Balance, beginning of year $ 1,185.1 $ 37.0 $ 1,337.9 $ 2,560.0 Capitalization 230.6 10.8 226.1 467.5 Amortization expense (199.2) (6.1) (153.4) (358.7) Foreign currency — (0.1) — (0.1) Balance, end of period $ 1,216.5 $ 41.6 $ 1,410.6 $ 2,668.7 September 30, 2024 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Dental and Vision Total Unum US (in millions of dollars) Balance, beginning of year $ 63.6 $ 48.9 $ 610.6 $ 497.8 $ 11.3 $ 1,232.2 Capitalization 48.1 31.0 93.2 63.9 11.2 247.4 Amortization expense (46.8) (26.7) (88.4) (45.3) (9.5) (216.7) Balance, end of period $ 64.9 $ 53.2 $ 615.4 $ 516.4 $ 13.0 $ 1,262.9 September 30, 2023 Group Disability Group Life and AD&D Voluntary Benefits Individual Disability Dental and Vision Total Unum US (in millions of dollars) Balance, beginning of year $ 61.0 $ 49.3 $ 601.0 $ 464.4 $ 9.4 $ 1,185.1 Capitalization 44.7 28.9 85.2 62.6 9.2 230.6 Amortization expense (42.1) (29.5) (79.5) (40.2) (7.9) (199.2) Balance, end of period $ 63.6 $ 48.7 $ 606.7 $ 486.8 $ 10.7 $ 1,216.5

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Premium Income by Major Line of Business within Each Segment	Segment information is shown below. Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Premium Income Unum US Group Disability Group Long-term Disability $ 522.1 $ 518.5 $ 1,560.3 $ 1,539.3 Group Short-term Disability 271.3 256.5 810.7 753.0 Group Life and Accidental Death & Dismemberment Group Life 447.8 423.0 1,337.9 1,254.3 Accidental Death & Dismemberment 47.1 44.1 139.3 131.2 Supplemental and Voluntary Voluntary Benefits 219.3 209.5 665.1 637.4 Individual Disability 140.4 136.7 424.6 386.7 Dental and Vision 75.5 69.4 223.9 206.8 1,723.5 1,657.7 5,161.8 4,908.7 Unum International Unum UK Group Long-term Disability 106.6 101.1 312.4 297.5 Group Life 58.8 44.2 156.3 124.5 Supplemental 41.4 34.6 125.1 99.9 Unum Poland 39.8 30.7 113.3 85.2 246.6 210.6 707.1 607.1 Colonial Life Accident, Sickness, and Disability 240.6 236.7 725.5 708.0 Life 113.1 106.2 342.6 318.1 Cancer and Critical Illness 88.2 88.3 266.9 265.2 441.9 431.2 1,335.0 1,291.3 Closed Block Long-term Care 173.7 172.1 521.5 521.2 All Other 43.1 54.3 140.9 166.0 216.8 226.4 662.4 687.2 Total Premium Income $ 2,628.8 $ 2,525.9 $ 7,866.3 $ 7,494.3
Selected Operating Statement Data by Segment	Unum US Unum International Colonial Life Closed Block Corporate Total (in millions of dollars) Three Months Ended September 30, 2024 Premium Income $ 1,723.5 $ 246.6 $ 441.9 $ 216.8 $ — $ 2,628.8 Net Investment Income 161.0 30.4 39.6 284.3 12.5 527.8 Other Income 60.1 0.4 0.4 12.4 — 73.3 Adjusted Operating Revenue $ 1,944.6 $ 277.4 $ 481.9 $ 513.5 $ 12.5 $ 3,229.9 Adjusted Operating Income (Loss) $ 363.3 $ 40.3 $ 113.4 $ 34.2 $ (49.4) $ 501.8 Three Months Ended September 30, 2023 Premium Income $ 1,657.7 $ 210.6 $ 431.2 $ 226.4 $ — $ 2,525.9 Net Investment Income 166.2 27.3 39.3 274.9 18.3 526.0 Other Income 58.0 0.5 0.3 12.8 — 71.6 Adjusted Operating Revenue $ 1,881.9 $ 238.4 $ 470.8 $ 514.1 $ 18.3 $ 3,123.5 Adjusted Operating Income (Loss) $ 357.8 $ 36.8 $ 102.9 $ 34.2 $ (41.5) $ 490.2 Unum US Unum International Colonial Life Closed Block Corporate Total (in millions of dollars) Nine Months Ended September 30, 2024 Premium Income $ 5,161.8 $ 707.1 $ 1,335.0 $ 662.4 $ — $ 7,866.3 Net Investment Income 476.1 94.5 119.4 851.6 44.8 1,586.4 Other Income 178.9 1.2 3.6 37.7 1.1 222.5 Adjusted Operating Revenue $ 5,816.8 $ 802.8 $ 1,458.0 $ 1,551.7 $ 45.9 $ 9,675.2 Adjusted Operating Income (Loss) $ 1,106.0 $ 120.2 $ 344.0 $ 110.1 $ (140.8) $ 1,539.5 Nine Months Ended September 30, 2023 Premium Income $ 4,908.7 $ 607.1 $ 1,291.3 $ 687.2 $ — $ 7,494.3 Net Investment Income 481.5 104.0 114.6 796.0 69.8 1,565.9 Other Income 166.1 1.0 0.9 40.1 2.5 210.6 Adjusted Operating Revenue $ 5,556.3 $ 712.1 $ 1,406.8 $ 1,523.3 $ 72.3 $ 9,270.8 Adjusted Operating Income (Loss) $ 1,013.4 $ 118.7 $ 312.3 $ 143.6 $ (109.9) $ 1,478.1
Assets by Segment	September 30 December 31 2024 2023 (in millions of dollars) Assets Unum US $ 15,365.4 $ 15,561.1 Unum International 3,569.4 3,372.9 Colonial Life 4,994.2 4,830.4 Closed Block 35,527.4 35,272.8 Corporate 4,684.1 4,218.0 Total Assets $ 64,140.5 $ 63,255.2
Reconciliation of Total Revenue and Income Before Income Tax to Adjusted Operating Revenue and Adjusted Operating Income	A reconciliation of total revenue to "adjusted operating revenue" and income before income tax to "adjusted operating income" is as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars) Total Revenue $ 3,217.0 $ 3,092.5 $ 9,650.7 $ 9,240.8 Excluding: Net Investment Loss (12.9) (31.0) (24.5) (30.0) Adjusted Operating Revenue $ 3,229.9 $ 3,123.5 $ 9,675.2 $ 9,270.8 Income Before Income Tax $ 814.6 $ 261.7 $ 1,805.8 $ 1,211.4 Excluding: Net Investment Loss (12.9) (31.0) (24.5) (30.0) Amortization of the Cost of Reinsurance (10.4) (11.1) (31.1) (33.1) Non-Contemporaneous Reinsurance (6.0) (9.2) (20.2) (26.4) Reserve Assumption Updates 357.4 (177.2) 357.4 (177.2) Loss on Legal Settlement (15.3) — (15.3) — Adjusted Operating Income $ 501.8 $ 490.2 $ 1,539.5 $ 1,478.1

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2024
Retirement Benefits [Abstract]
Schedule of Net Benefit Costs	The following table provides the components of the net periodic benefit cost (credit) for the defined benefit pension and OPEB plans. Three Months Ended September 30 Pension Benefits U.S. Plans U.K. Plan OPEB 2024 2023 2024 2023 2024 2023 (in millions of dollars) Service Cost $ 2.3 $ 2.3 $ — $ — $ — $ — Interest Cost 20.7 22.0 1.9 1.9 1.0 1.1 Expected Return on Plan Assets (22.8) (23.0) (2.1) (2.1) (0.1) (0.2) Amortization of: Net Actuarial (Gain) Loss 3.7 3.8 0.7 0.6 (0.2) (2.6) Prior Service Credit — — — — (0.1) — Total Net Periodic Benefit Cost (Credit) $ 3.9 $ 5.1 $ 0.5 $ 0.4 $ 0.6 $ (1.7) Nine Months Ended September 30 Pension Benefits U.S. Plans U.K. Plan OPEB 2024 2023 2024 2023 2024 2023 (in millions of dollars) Service Cost $ 6.9 $ 6.9 $ — $ — $ — $ — Interest Cost 62.1 66.0 5.7 5.7 3.0 3.4 Expected Return on Plan Assets (68.4) (69.1) (6.3) (6.3) (0.3) (0.4) Amortization of: Net Actuarial (Gain) Loss 11.0 11.4 2.2 1.9 (0.8) (7.9) Prior Service Credit — — — — (0.2) (0.1) Total Net Periodic Benefit Cost (Credit) $ 11.6 $ 15.2 $ 1.6 $ 1.3 $ 1.7 $ (5.0)

Stockholders' Equity and Earn_2

Stockholders' Equity and Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity and Earnings Per Common Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	Net income per common share is determined as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions of dollars, except share data) Numerator Net Income $ 645.7 $ 202.0 $ 1,430.4 $ 953.2 Denominator (000s) Weighted Average Common Shares - Basic 186,400.7 196,083.2 189,665.1 197,289.5 Dilution for Assumed Exercises of Nonvested Stock Awards 481.7 1,048.6 544.6 1,005.6 Weighted Average Common Shares - Assuming Dilution 186,882.4 197,131.8 190,209.7 198,295.1 Net Income Per Common Share Basic $ 3.46 $ 1.03 $ 7.54 $ 4.83 Assuming Dilution $ 3.46 $ 1.02 $ 7.52 $ 4.81
Treasury Stock Transactions	Common stock repurchases, which are accounted for using the cost method and classified as treasury stock until otherwise retired, were as follows: Three Months Ended September 30 Nine Months Ended September 30 2024 2023 2024 2023 (in millions) Shares Repurchased 3.7 1.5 9.7 3.9 Cost of Shares Repurchased 1 $ 202.0 $ 74.8 $ 504.8 $ 175.4 1 Includes a de minimis amount of commissions for the three and nine months ended September 30, 2024 and a de minimis amount and $0.1 million of commissions for the three and nine months ended September 30, 2023, respectively. Also includes $2.0 million and $4.8 million of excise tax for the three and nine months ended September 30, 2024, respectively, and $0.7 million and $1.2 million of excise tax for the three and nine months ended September 30, 2023, respectively. As a part of our share repurchase program, we periodically enter into accelerated share repurchase agreements (ASR). Under the terms of these agreements, we make a prepayment to a financial counterparty for which we receive an initial delivery of approximately 75 percent of the total Unum Group common stock to be delivered under the agreement. We simultaneously enter into a forward contract indexed to the price of Unum Group common stock, which subjects the transactions to a future price adjustment. Under the terms of the agreements, we are to receive, or be required to pay, a price adjustment based on the volume weighted average price of Unum Group common stock during the term of the agreement, less a discount. Any price adjustment payable to us is settled in shares of Unum Group common stock. Any price adjustment we would be required to pay may be settled in either cash or common stock at our option. Details of our ASRs are as follows: Prepayment Date Prepayment Amount Initial Share Delivery Forward Contract Settlement Date Shares Delivered to Settle Forward Contract (in millions) October 2024 $150.0 1.9 December 2024 Not yet settled July 2024 $150.0 2.2 September 2024 0.6 April 2024 $125.0 1.7 June 2024 0.7 January 2024 $100.0 1.6 March 2024 0.5 July 2023 $50.0 0.8 September 2023 0.2

Fair Values of Financial Inst_3

Fair Values of Financial Instruments Private Equity Partnerships (Details) - Private Equity Partnerships - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		$ 1,428	$ 1,326.2
Alternative Investments, Unfunded Commitments		805.6	803.1
Private Credit
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		297	283.6
Alternative Investments, Unfunded Commitments		132.3	136.8
Private Credit | Not Redeemable
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments	[1]	246.3	239.1
Alternative Investments, Unfunded Commitments		126.1	128.2
Private Credit | Quarterly / 90 days notice
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		50.7	44.5
Alternative Investments, Unfunded Commitments		6.2	8.6
Private Equity Limited Partnership
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		608.1	571.9
Alternative Investments, Unfunded Commitments		430.4	427.2
Private Equity Limited Partnership | Not Redeemable
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments	[2]	574.8	543.9
Alternative Investments, Unfunded Commitments		417.2	410.6
Private Equity Limited Partnership | Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		33.3	28
Alternative Investments, Unfunded Commitments		13.2	16.6
Real Assets
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		522.9	470.7
Alternative Investments, Unfunded Commitments		242.9	239.1
Real Assets | Not Redeemable
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments	[3]	488.8	437.5
Alternative Investments, Unfunded Commitments		242.9	239.1
Real Assets | Quarterly / 90 days notice
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		34.1	33.2
Alternative Investments, Unfunded Commitments		$ 0	$ 0
[1] Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North America and, to a lesser extent, outside of North America. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 80 percent in the next 3 years, 12 percent during the period from 3 to 5 years, and 8 percent during the period from 5 to 10 years. Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 36 percent in the next 3 years, 31 percent during the period from 3 to 5 years, and 33 percent during the period from 5 to 10 years. Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia. As of September 30, 2024, the estimated remaining life of the investments that do not allow for redemptions is approximately 38 percent in the next 3 years, 26 percent during period from 3 to 5 years, 34 percent during the period from 5 to 10 years, and 2 percent during the period from 10 to 15 years.

Fair Value Measurements by Inpu

Fair Value Measurements by Input Level (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets, Fair Value Disclosure
Fixed Maturity Securities	$ 37,783.5	$ 36,833.9
Derivative Assets	Other Long-term Investments	Other Long-term Investments
Equity Securities	$ 21.8	$ 31.9
Other Long-term Investments	1,682.8	1,579.4
Assets, Fair Value Disclosure	39,343.4	38,291.9
Derivative Assets	$ 110.1	$ 99.9
Liabilities
Derivative Liabilities location	Other Liabilities	Other Liabilities
Liabilities, Fair Value Disclosure	$ 130.2	$ 117.7
Derivative Liabilities	130.2	117.7
Forwards
Liabilities
Derivative Liabilities	95.2	78
Foreign Exchange Contracts
Liabilities
Derivative Liabilities	35	38.2
Embedded Derivative in Modified Coinsurance Arrangement
Liabilities
Derivative Liabilities		1.5
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure
Other Long-term Investments	1,559.9	1,458
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	7,964.9	4,286.5
Equity Securities	0	0
Other Long-term Investments	0	0
Assets, Fair Value Disclosure	7,964.9	4,286.5
Liabilities
Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	29,739.6	32,391.1
Equity Securities	0.1	10.3
Other Long-term Investments	105.6	110.2
Assets, Fair Value Disclosure	29,845.2	32,501.3
Derivative Assets	105.5	99.9
Liabilities
Liabilities, Fair Value Disclosure	130.2	116.2
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Forwards
Liabilities
Derivative Liabilities	95.2	78
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Foreign Exchange Contracts
Liabilities
Derivative Liabilities	35	38.2
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	79	156.3
Equity Securities	21.7	21.6
Other Long-term Investments	26.3	21.6
Assets, Fair Value Disclosure	105.3	177.9
Derivative Assets	4.6
Liabilities
Liabilities, Fair Value Disclosure	0	1.5
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Embedded Derivative in Modified Coinsurance Arrangement
Liabilities
Derivative Liabilities		1.5
Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Equity Securities	0	0
Other Long-term Investments	1,428	1,326.2
Assets, Fair Value Disclosure	1,428	1,326.2
Liabilities
Liabilities, Fair Value Disclosure	0	0
United States Government and Government Agencies and Authorities
Assets, Fair Value Disclosure
Fixed Maturity Securities	557.4	624.8
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	557.4	624.8
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
States, Municipalities, and Political Subdivisions
Assets, Fair Value Disclosure
Fixed Maturity Securities	3,526.5	3,678.4
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	3,526.5	3,678.4
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Foreign Governments
Assets, Fair Value Disclosure
Fixed Maturity Securities	850.1	890.7
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	850.1	890.7
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Public Utilities
Assets, Fair Value Disclosure
Fixed Maturity Securities	5,585.2	5,321.6
Public Utilities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	602.7	301.3
Public Utilities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	4,982.5	5,020.3
Public Utilities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Public Utilities | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Mortgage/Asset-backed Securities
Assets, Fair Value Disclosure
Fixed Maturity Securities	850.6	644.1
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	799.6	611.2
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	51	32.9
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
All Other Corporate Bonds
Assets, Fair Value Disclosure
Fixed Maturity Securities	26,406	25,670.7
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	7,362.2	3,985.2
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	19,015.8	21,562.1
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	28	123.4
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Redeemable Preferred Stocks
Assets, Fair Value Disclosure
Fixed Maturity Securities	7.7	3.6
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Fixed Maturity Securities	7.7	3.6
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Fixed Maturity Securities	0	0
Forwards
Assets, Fair Value Disclosure
Derivative Assets	49.5	47.5
Forwards | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Derivative Assets	49.5	47.5
Foreign Exchange Contracts
Assets, Fair Value Disclosure
Derivative Assets	56	52.4
Foreign Exchange Contracts | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Derivative Assets	56	52.4
Embedded Derivative in Modified Coinsurance Arrangement
Assets, Fair Value Disclosure
Derivative Assets	4.6
Embedded Derivative in Modified Coinsurance Arrangement | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Derivative Assets	4.6
Private Equity Partnerships
Assets, Fair Value Disclosure
Alternative Investments	1,428	1,326.2
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure
Alternative Investments	0	0
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure
Alternative Investments	0	0
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure
Alternative Investments	0	0
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets, Fair Value Disclosure
Alternative Investments	1,428	1,326.2
Derivatives | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Liabilities
Derivative Liabilities	$ 130.2	116.2
Derivatives | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Liabilities
Derivative Liabilities		$ 1.5

Changes in Assets and Liabiliti

Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs (Level 3) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Embedded Derivative in Modified Coinsurance Arrangement
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	$ 0	$ 0	$ 0	$ 0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	(0.8)	9.3	6.1	14.8
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	4.6	0.9	4.6	0.9	$ 5.4	$ (1.5)	$ (8.4)	$ (13.9)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(0.8)	9.3	6.1	14.8
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Sales	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3	0	0	0	0
US States and Political Subdivisions Debt Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		0		0				0.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales/Maturities				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3				(0.2)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI				0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)				0
Public Utilities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0	0	0	0	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(0.2)	(0.1)	(0.2)	0.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.7	0.1	0.3	(0.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales/Maturities	(10.3)	(3.9)	(10.3)	(7.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	9.8	3.9	10.2	7.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0	0	0
Mortgage/Asset-backed Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	51	45.2	51	45.2	46.5	32.9	24.1	22
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.2	(1.4)	0.6	(1.5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	4.9	19	15.5	29.9
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales/Maturities	(0.7)	(1)	(1.9)	(2.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0.1	4.7	3.9	6.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	(0.2)	0	(9)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0.2	(1.4)	0.6	(1.5)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0	0	0
All Other Corporate Bonds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	28	108.3	28	108.3	53.3	123.4	128.8	158.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	(4.6)	(2.6)	(5.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	2	2	6.9	(20.6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	2.3	1.5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales/Maturities	(42.2)	(54.9)	(196.4)	(229.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	39.1	87.5	189	276
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	(24.2)	(50.5)	(94.6)	(72.4)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	2	2	6.9	(20.6)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0	(2.6)	0
Fixed Maturity Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	79	153.5	79	153.5	99.8	156.3	152.9	180.9
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(0.2)	(4.7)	(2.8)	(5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	2.9	0.7	7.8	(22.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	4.9	19	17.8	31.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales/Maturities	(53.2)	(59.8)	(208.6)	(239.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	49	96.1	203.1	289.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	(24.2)	(50.7)	(94.6)	(81.6)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	2.2	0.6	7.5	(22.1)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0	(2.6)	0
Equity Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	21.7	17.5	21.7	17.5	$ 21.7	$ 21.6	$ 17.5	$ 16.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0	0.1	0.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	0	0.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales/Maturities	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	$ 0	$ 0	$ 0.1	$ 0.6

Quantitative Information Regard

Quantitative Information Regarding Significant Unobservable Inputs (Details) $ in Millions		Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity Securities		$ 21.8	$ 31.9
Fixed Maturity Securities		37,783.5	36,833.9
Fair Value, Inputs, Level 3 | Discounted Cash Flow | Embedded Derivative in Modified Coinsurance Arrangement
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative in Modified Coinsurance Arrangement		$ 4.6	$ (1.5)
Fair Value, Inputs, Level 3 | Discounted Cash Flow | Embedded Derivative in Modified Coinsurance Arrangement | Weighted Average | Spread of Swap Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Liability, Measurement Input	[1]	(0.00031)	0.002
Fair Value, Inputs, Level 3 | Equity Securities | Market Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity Securities		$ 21.7	$ 21.6
Fair Value, Inputs, Level 3 | Corporate Debt Securities - Private | Market Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed Maturity Securities		$ 16.3	$ 15.9
Fair Value, Inputs, Level 3 | Corporate Debt Securities - Private | Market Approach | Minimum | Volatility of Credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input	[2]	0.0500	0.0500
Fair Value, Inputs, Level 3 | Corporate Debt Securities - Private | Market Approach | Maximum | Volatility of Credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input	[2]	0.0500	0.0500
Fair Value, Inputs, Level 3 | Corporate Debt Securities - Private | Market Approach | Weighted Average | Volatility of Credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input	[2]	0.0500	0.0500
[1] Represents various actuarial assumptions required to derive the liability cash flows. Fair value of embedded derivative is most often driven by the change in the weighted average credit spread to the swap curve for the assets backing the hypothetical loan Represents basis point adjustments for credit-specific factors

Fair Values of Financial Inst_4

Fair Values of Financial Instruments Carrying Amounts and Estimated Fair value of Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Carrying Amount	$ 2,238.9	$ 2,318.2
Policy Loans	3,625.6	3,620.2
Long-term Debt	3,470.4	3,430.4
Liabilities, Fair Value Disclosure	130.2	117.7
Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	2,041.8	2,070.7
Mortgage Loans, Carrying Amount	2,238.9	2,318.2
Policy Loans, Fair Value Disclosure	3,708.6	3,696.3
Policy Loans	3,625.6	3,620.2
Miscellaneous Long-Term Investments, Fair Value Disclosure	25.9	16
Miscellaneous Long-Term Investments, Carrying Value	25.9	16
Financial Instruments, Financial Assets Fair Value Disclosure	5,776.3	5,783
Total Financial Instrument Assets Not Carried at Fair Value	5,890.4	5,954.4
Long-term Debt, Fair Value Disclosure	3,392.3	3,227.9
Long-term Debt	3,470.4	3,430.4
Unfunded Commitments	0.2	0.2
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	299	64.5
Payables for Collateral on Investments	299	64.5
Liabilities, Fair Value Disclosure	3,691.5	3,292.6
Total Financial Instrument Liabilities Not Carried at Fair Value	3,769.6	3,495.1
Fair Value, Inputs, Level 1 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	0	0
Policy Loans, Fair Value Disclosure	0	0
Miscellaneous Long-Term Investments, Fair Value Disclosure	0	0
Financial Instruments, Financial Assets Fair Value Disclosure	0	0
Long-term Debt, Fair Value Disclosure	3,347.8	2,629.1
Unfunded Commitments	0	0
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	3,347.8	2,629.1
Fair Value, Inputs, Level 2 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	2,041.8	2,070.7
Policy Loans, Fair Value Disclosure	0	0
Miscellaneous Long-Term Investments, Fair Value Disclosure	25.6	15.7
Financial Instruments, Financial Assets Fair Value Disclosure	2,067.4	2,086.4
Long-term Debt, Fair Value Disclosure	44.5	598.8
Unfunded Commitments	0.2	0.2
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	299	64.5
Liabilities, Fair Value Disclosure	343.7	663.5
Fair Value, Inputs, Level 3 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	0	0
Policy Loans, Fair Value Disclosure	3,708.6	3,696.3
Miscellaneous Long-Term Investments, Fair Value Disclosure	0.3	0.3
Financial Instruments, Financial Assets Fair Value Disclosure	3,708.9	3,696.6
Long-term Debt, Fair Value Disclosure	0	0
Unfunded Commitments	0	0
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	$ 0	$ 0

Fair Value of Financial Instrum

Fair Value of Financial Instruments Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Ceded Policy Loans	$ 3,320.4	$ 3,322.5
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	21.10%
Fair Value, Inputs, Level 2 | Pricing Service
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	62.80%
Fair Value, Inputs, Level 2 | Other Observable Market Data
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	15.60%
Fair Value Inputs Other Than Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	78.90%
Fair Value Inputs Level 2 Or Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	0.50%

Amortized Cost and Fair Values

Amortized Cost and Fair Values of Securities by Security Type (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	$ 38,822.6		$ 38,410.6
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	2.9		2.2	$ 0	$ 0	$ 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,338.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,374.4
Debt Securities, Available-for-sale, Total	37,783.5		36,833.9
United States Government and Government Agencies and Authorities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	542.5		618.6
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	28.8		25.3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	13.9		19.1
Debt Securities, Available-for-sale, Total	557.4		624.8
States, Municipalities, and Political Subdivisions
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	3,843.4		4,041.3
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	118.7		135.3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	435.6		498.2
Debt Securities, Available-for-sale, Total	3,526.5		3,678.4
Foreign Governments
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	964.8		982.1
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	22.4		29.8
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	137.1		121.2
Debt Securities, Available-for-sale, Total	850.1		890.7
Public Utilities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	5,561.8		5,398.2
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	272.3		217.1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	248.9		293.7
Debt Securities, Available-for-sale, Total	5,585.2		5,321.6
Mortgage/Asset-backed Securities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	853.8		658
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	13.2		10.1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	16.4		24
Debt Securities, Available-for-sale, Total	850.6		644.1
All Other Corporate Bonds
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	27,048.3		26,708.4
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	2.9	$ 5.1	2.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	882.8		771.8
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,522.2		1,807.3
Debt Securities, Available-for-sale, Total	26,406		25,670.7
Redeemable Preferred Stocks
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	8		4
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0.3		0.4
Debt Securities, Available-for-sale, Total	7.7		3.6
Fixed Maturity Securities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	38,822.6		38,410.6
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	2.9		2.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,338.2		1,189.4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 2,374.4		$ 2,763.9

Length of Time Fixed Maturity S

Length of Time Fixed Maturity Securities had been in a Gross Unrealized Loss Position (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
United States Government and Government Agencies and Authorities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 27.4	$ 118.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.3	0.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	211.4	197.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	13.6	18.4
States, Municipalities, and Political Subdivisions
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	145	128
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2.5	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,061	2,035.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	433.1	494.2
Foreign Governments
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	50.5	149.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1.7	3.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	320.5	312.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	135.4	117.9
Public Utilities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	243.6	373.7
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	7.4	10.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,651.5	1,720.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	241.5	283.3
Mortgage/Asset-backed Securities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	81.3	60.3
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.2	2.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	304.3	316.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	16.2	21.5
All Other Corporate Bonds
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,013.2	1,483.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9.6	26.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	13,185.8	14,215.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,512.6	1,780.5
Redeemable Preferred Stocks
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	3.7	3.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.3	0.4
Fixed Maturity Securities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,561	2,314.5
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	21.7	47.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	17,738.2	18,801.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 2,352.7	$ 2,716.2

Investments Distribution of the

Investments Distribution of the Maturity Dates for Fixed Maturity Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale, Amortized Cost, Net of Allowance for Credit Losses, Fiscal Year Maturity
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One, Net	$ 1,289.6	$ 935
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five, Net	8,125.2	7,594.4
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10, Net	8,550	9,430.3
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10, Net	20,001.1	19,790.7
Available for sale Securities Debt Maturities Amortized Cost Gross Subtotal, Net	37,965.9	37,750.4
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost, Net	853.8	658
Debt Securities, Available-for-sale, Amortized Cost, Net of Allowance for Credit Losses	38,819.7	38,408.4
Available for Sale Securities Unrealized Gain Position Gross Gain
Available For Sale Securities Debt Maturities Within One Year Unrealized Gain Position Gross Gain	2.6	0.9
Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Gain Position Gross Gain	180.7	128.2
Available For Sale Securities Debt Maturities After Five Through Ten Years Unrealized Gain Position Gross Gain	387	372.1
Available For Sale Securities Debt Maturities After Ten Years Unrealized Gain Position Gross Gain	754.7	678.1
Available For Sale Securities Debt Maturities Unrealized Gain Position Gross Gain Gross Subtotal	1,325	1,179.3
Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Gain Position Gross Gain	13.2	10.1
Available for sale Securities, Debt Maturities Unrealized Gain Position Gross Gain	1,338.2	1,189.4
Available for Sale Securities Unrealized Loss Position Gross Loss
Available For Sale Securities Debt Maturities Within One Year Unrealized Loss Position Gross Loss	5.5	7.5
Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Loss Position Gross Loss	126.9	179
Available For Sale Securities Debt Maturities After Five Through Ten Years Unrealized Loss Position Gross Loss	442.7	610.8
Available For Sale Securities Debt Maturities After Ten Years Unrealized Loss Position Gross Loss	1,782.9	1,942.6
Available For Sale Securities Debt Maturities Unrealized Gain Position Gross Loss Gross Subtotal	2,358	2,739.9
Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Loss Position Gross Loss	16.4	24
Available For Sale Securities Unrealized Loss Position Gross Loss Subtotal	2,374.4	2,763.9
Fair Value Maturity Distribution
Debt Securities, Available-for-sale, Total	37,783.5	36,833.9
Available for Sale Securities Unrealized Gain Position Fair Value
Fair Value Maturity Distribution
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	342	140.8
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	3,864.2	2,685.7
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	4,462.2	4,100
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	9,350.9	8,524.4
Available for sale Securities Debt Maturities Fair Value Gross Subtotal	18,019.3	15,450.9
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	465	267.1
Debt Securities, Available-for-sale, Total	18,484.3	15,718
Available for Sale Securities Unrealized Loss Position Fair Value
Fair Value Maturity Distribution
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	944.7	787.6
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	4,314.8	4,857.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	4,032.1	5,091.6
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	9,622	10,001.8
Available for sale Securities Debt Maturities Fair Value Gross Subtotal	18,913.6	20,738.9
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	385.6	377
Debt Securities, Available-for-sale, Total	$ 19,299.2	$ 21,115.9

Investments Distribution by Ext

Investments Distribution by External Credit Rating for Fixed Maturity Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale
Fixed Maturity Securities	$ 37,783.5	$ 36,833.9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,338.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 2,374.4
Fixed maturity securities in unrealized loss position percent of total	100%
External Credit Rating, Investment Grade
Debt Securities, Available-for-sale
Fixed Maturity Securities	$ 36,287.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,308.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 2,308.8
Fixed maturity securities in unrealized loss position percent of total	97.20%
External Credit Rating, Below-Investment-Grade
Debt Securities, Available-for-sale
Fixed Maturity Securities	$ 1,496.3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 65.6
Fixed maturity securities in unrealized loss position percent of total	2.80%

Debt Securities, Available-for-

Debt Securities, Available-for-sale, Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Securities, Available-for-sale, Allowance for Credit Loss
Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance		$ 0	$ 2.2	$ 0
Debt Securities, Available-for-sale, Credit losses on securities for which credit losses were not previously recorded				0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Change in allowance due to change in intent to hold securities to maturity		0		0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	$ 2.9	0	2.9	0
All Other Corporate Bonds
Debt Securities, Available-for-sale, Allowance for Credit Loss
Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	5.1		2.2
Debt Securities, Available-for-sale, Credit losses on securities for which credit losses were not previously recorded			2.9
Debt Securities, Available-for-sale, Allowance for Credit Loss, Change in allowance due to change in intent to hold securities to maturity	0.2		0.2
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(2.4)	$ 0	(2.4)	$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	$ 2.9		$ 2.9

Mortgage Loans by Property Type

Mortgage Loans by Property Type and Geographic Region (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 2,238.9	$ 2,318.2
Mortgage Loans, Percent of Total	100%	100%
New England
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 53.2	$ 55.1
Mortgage Loans, Percent of Total	2.40%	2.40%
Mid-Atlantic
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 162.4	$ 155.1
Mortgage Loans, Percent of Total	7.30%	6.70%
East North Central
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 294	$ 314.4
Mortgage Loans, Percent of Total	13.10%	13.60%
West North Central
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 158.9	$ 163.5
Mortgage Loans, Percent of Total	7.10%	7%
South Atlantic
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 537.1	$ 553
Mortgage Loans, Percent of Total	24%	23.80%
East South Central
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 107.8	$ 110.7
Mortgage Loans, Percent of Total	4.80%	4.80%
West South Central
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 195.5	$ 200.9
Mortgage Loans, Percent of Total	8.70%	8.70%
Mountain
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 269.5	$ 282.7
Mortgage Loans, Percent of Total	12%	12.20%
Pacific
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 460.5	$ 482.8
Mortgage Loans, Percent of Total	20.60%	20.80%
Apartment
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 662.9	$ 685.8
Mortgage Loans, Percent of Total	29.60%	29.60%
Industrial
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 684.2	$ 706
Mortgage Loans, Percent of Total	30.60%	30.50%
Office
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 354.1	$ 379.9
Mortgage Loans, Percent of Total	15.80%	16.40%
Retail
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 496.1	$ 503.9
Mortgage Loans, Percent of Total	22.10%	21.70%
Other Property
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 41.6	$ 42.6
Mortgage Loans, Percent of Total	1.90%	1.80%

Schedule of Participating Mortg

Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 2,238.9	$ 2,318.2
Mortgage Loans, Percent of Total	100%	100%
Loan to Value Ratio Below or Equal to 65 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 1,527	$ 1,409.9
Mortgage Loans, Percent of Total	68.20%	60.80%
Loan To Value Ratio Above 65 To 75 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 481.6	$ 707
Mortgage Loans, Percent of Total	21.50%	30.50%
Loan To Value Ratio Above 75 To 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 148.5	$ 136.5
Mortgage Loans, Percent of Total	6.60%	5.90%
Loan To Value Ratio Above 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 81.8	$ 64.8
Mortgage Loans, Percent of Total	3.70%	2.80%
AA Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 94.5	$ 85.2
Mortgage Loans, Percent of Total	4.20%	3.70%
A Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 982.2	$ 942.5
Mortgage Loans, Percent of Total	43.90%	40.60%
BBB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 1,064.4	$ 1,249.5
Mortgage Loans, Percent of Total	47.50%	53.90%
BB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 97.8	$ 41
Mortgage Loans, Percent of Total	4.40%	1.80%

Mortgage Loans, Sorted by Appli

Mortgage Loans, Sorted by Applicable Credit Quality Indicators (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	$ 2,238.9		$ 2,318.2
Loan to Value Ratio Below or Equal to 65 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	1,527		1,409.9
Loan To Value Ratio Above 65 To 75 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	481.6		707
Loan To Value Ratio Above 75 To 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	148.5		136.5
Loan To Value Ratio Above 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	81.8		64.8
Originated Five or More Years before Last Fiscal Year
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	1,574.9		1,317.6
Originated Four Years before Last Fiscal Year
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	155.2		334.8
Originated Three Years before Last Fiscal Year
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	331.4		164.9
Originated Two Years before Last Fiscal Year
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	87.8		347.1
Originated in Fiscal Year before Latest Fiscal Year
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	66.6		87
Originated in Current Fiscal Year
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	23		66.8
Commercial Real Estate
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	1,589		1,323.9
Financing Receivable, Originated Four Years before Latest Fiscal Year	155.7		336.1
Financing Receivable, Originated Three Years before Latest Fiscal Year	332.5		165.5
Financing Receivable, Originated Two Years before Latest Fiscal Year	88.1		348.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	67		87.6
Financing Receivable, Originated in Current Fiscal Year	23.1		67.2
Financing Receivable, before Allowance for Credit Loss	2,255.4		2,328.4
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	16.5		10.2
Commercial Real Estate | Loan to Value Ratio Below or Equal to 65 Percent
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	1,174.1		908.3
Financing Receivable, Originated Four Years before Latest Fiscal Year	113.7		197.7
Financing Receivable, Originated Three Years before Latest Fiscal Year	188.8		116.4
Financing Receivable, Originated Two Years before Latest Fiscal Year	15.6		145.2
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	38.7		16.2
Financing Receivable, Originated in Current Fiscal Year	0		30
Financing Receivable, before Allowance for Credit Loss	1,530.9		1,413.8
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	4	$ 3.7	3.8	$ 3.2	$ 3.3	$ 3
Commercial Real Estate | Loan To Value Ratio Above 65 To 75 Percent
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	231.2		252.1
Financing Receivable, Originated Four Years before Latest Fiscal Year	33.9		138.4
Financing Receivable, Originated Three Years before Latest Fiscal Year	94.9		40.8
Financing Receivable, Originated Two Years before Latest Fiscal Year	72.5		171
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	28.3		71.4
Financing Receivable, Originated in Current Fiscal Year	23.1		37.2
Financing Receivable, before Allowance for Credit Loss	483.9		710.9
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	2.2	3.3	3.8	4.4	4.8	4.7
Commercial Real Estate | Loan To Value Ratio Above 75 To 85 Percent
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	122.6		97.3
Financing Receivable, Originated Four Years before Latest Fiscal Year	8.1		0
Financing Receivable, Originated Three Years before Latest Fiscal Year	20.3		8.3
Financing Receivable, Originated Two Years before Latest Fiscal Year	0		31.9
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0		0
Financing Receivable, Originated in Current Fiscal Year	0		0
Financing Receivable, before Allowance for Credit Loss	151		137.5
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	2.5	1.7	1.2	0.9	0.9	1.1
Commercial Real Estate | Loan To Value Ratio Above 85 Percent
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	61.1		66.2
Financing Receivable, Originated Four Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Three Years before Latest Fiscal Year	28.5		0
Financing Receivable, Originated Two Years before Latest Fiscal Year	0		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0		0
Financing Receivable, Originated in Current Fiscal Year	0		0
Financing Receivable, before Allowance for Credit Loss	89.6		66.2
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	7.8	$ 3.4	1.4	$ 1.7	$ 2.1	$ 0.5
Commercial Real Estate | Originated Five or More Years before Last Fiscal Year
Mortgage Loans on Real Estate
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	14.1		6.3
Commercial Real Estate | Originated Four Years before Last Fiscal Year
Mortgage Loans on Real Estate
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	0.5		1.3
Commercial Real Estate | Originated Three Years before Last Fiscal Year
Mortgage Loans on Real Estate
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	1.1		0.6
Commercial Real Estate | Originated Two Years before Last Fiscal Year
Mortgage Loans on Real Estate
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	0.3		1
Commercial Real Estate | Originated in Fiscal Year before Latest Fiscal Year
Mortgage Loans on Real Estate
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	0.4		0.6
Commercial Real Estate | Originated in Current Fiscal Year
Mortgage Loans on Real Estate
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	0.1		0.4
AA Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	94.5		85.2
AA Credit Rating | Commercial Real Estate
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	88.1		74.3
Financing Receivable, Originated Four Years before Latest Fiscal Year	0		11
Financing Receivable, Originated Three Years before Latest Fiscal Year	6.4		0
Financing Receivable, Originated Two Years before Latest Fiscal Year	0		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0		0
Financing Receivable, Originated in Current Fiscal Year	0		0
Financing Receivable, before Allowance for Credit Loss	94.5		85.3
A Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	982.2		942.5
A Credit Rating | Commercial Real Estate
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	684.4		589
Financing Receivable, Originated Four Years before Latest Fiscal Year	92.6		100.3
Financing Receivable, Originated Three Years before Latest Fiscal Year	145		94.1
Financing Receivable, Originated Two Years before Latest Fiscal Year	24.3		100.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	38		23.2
Financing Receivable, Originated in Current Fiscal Year	0		38
Financing Receivable, before Allowance for Credit Loss	984.3		944.7
BBB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	1,064.4		1,249.5
BBB Credit Rating | Commercial Real Estate
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	710.4		618.4
Financing Receivable, Originated Four Years before Latest Fiscal Year	63.1		224.8
Financing Receivable, Originated Three Years before Latest Fiscal Year	181.1		71.4
Financing Receivable, Originated Two Years before Latest Fiscal Year	63.8		248
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	29		64.4
Financing Receivable, Originated in Current Fiscal Year	23.1		29.2
Financing Receivable, before Allowance for Credit Loss	1,070.5		1,256.2
BB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans, Carrying Amount	97.8		41
BB Credit Rating | Commercial Real Estate
Mortgage Loans on Real Estate
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	106.1		42.2
Financing Receivable, Originated Four Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Three Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Two Years before Latest Fiscal Year	0		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0		0
Financing Receivable, Originated in Current Fiscal Year	0		0
Financing Receivable, before Allowance for Credit Loss	$ 106.1		$ 42.2

Mortgage Loans, Allowance for C

Mortgage Loans, Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Current Period Provisions	$ 4.5		$ (0.9)	$ 6.4	$ 0.9
Write-offs		$ 0		0
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Financing Receivable, Allowance for Credit Loss, Beginning Balance		10.2		10.2
Financing Receivable, Allowance for Credit Loss, Ending Balance	16.5			16.5
Commercial Real Estate | Loan to Value Ratio Below or Equal to 65 Percent
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Financing Receivable, Allowance for Credit Loss, Beginning Balance	3.7	3.8	3.3	3.8	3
Current Period Provisions	0.3		(0.1)	0.2	0.2
Write-offs	0		0	0	0
Recoveries	0		0	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	4		3.2	4	3.2
Commercial Real Estate | Loan To Value Ratio Above 65 To 75 Percent
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Financing Receivable, Allowance for Credit Loss, Beginning Balance	3.3	3.8	4.8	3.8	4.7
Current Period Provisions	(1.1)		(0.4)	(1.6)	(0.3)
Write-offs	0		0	0	0
Recoveries	0		0	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	2.2		4.4	2.2	4.4
Commercial Real Estate | Loan To Value Ratio Above 75 To 85 Percent
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Financing Receivable, Allowance for Credit Loss, Beginning Balance	1.7	1.2	0.9	1.2	1.1
Current Period Provisions	0.8		0	1.3	(0.2)
Write-offs	0		0	0	0
Recoveries	0		0	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	2.5		0.9	2.5	0.9
Commercial Real Estate | Loan To Value Ratio Above 85 Percent
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Financing Receivable, Allowance for Credit Loss, Beginning Balance	3.4	1.4	2.1	1.4	0.5
Current Period Provisions	4.4		(0.4)	6.4	1.2
Write-offs	0		0	0	0
Recoveries	0		0	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	7.8		1.7	7.8	1.7
Commercial Real Estate | Loan to Value Ratio Total
Financing Receivable, Allowance for Credit Loss Rollforward, Mortgage Loans
Financing Receivable, Allowance for Credit Loss, Beginning Balance	12.1	$ 10.2	11.1	10.2	9.3
Current Period Provisions	4.4		(0.9)	6.3	0.9
Write-offs	0		0	0	0
Recoveries	0		0	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	$ 16.5		$ 10.2	$ 16.5	$ 10.2

Investments Remaining Contractu

Investments Remaining Contractual Maturity of Secruity Lending Agreements (Details) - Overnight and Continuous - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	$ 25.8	$ 63.1
Securities Loaned and Securities Sold under Agreement to Repurchase, Gross Including Not Subject to Master Netting Arrangement	25.8	63.1
Secured Borrowings, Gross, Difference, Amount	0	0
Public Utilities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	3.7	1.8
All Other Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	$ 22.1	$ 61.3

Investments Federal Home Loan B

Investments Federal Home Loan Bank Carrying Amount, Collateral Posted and Advances Received (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank Common Stock	$ 25.6	$ 15.7
Federal Home Loan Bank, Advances	299	64.5
Federal Home Loan Bank, Collateral Posted to FHLB	1,541.3	1,575.8
Fixed Maturity Securities
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank, Collateral Posted to FHLB	600.7	589
Commercial Mortgage Loans
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank, Collateral Posted to FHLB	$ 940.6	$ 986.8

Investments Schedule of Financi

Investments Schedule of Financial Instrument and Derivative Offsetting (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Offsetting Derivative Assets
Net Derivative Assets Reported in Balance Sheet	$ 110.1	$ 99.9
Offsetting Securities Loaned
Gross Securities Loaned	57.9	72
Assets Offsetting Securities Loaned in Balance Sheet	0	0
Net Securities Loaned Reported in Balance Sheet	57.9	72
Securities Given as Collateral on Securities Loaned	(32.1)	(8.9)
Cash Given as Collateral on Securities Loaned	(25.8)	(63.1)
Securities Loaned Net of Collateral	0	0
Offsetting Financial Assets
Gross Financial Assets	163.4	171.9
Financial Liabilities Offsetting Financial Assets in Balance Sheet	0	0
Net Financial Assets Reported in Balance Sheet	163.4	171.9
Securities Received as Collateral on Financial Assets	(135)	(100.8)
Cash Received as Collateral on Financial Assets	(28.1)	(69.5)
Financial Assets Net of Collateral	0.3	1.6
Offsetting Derivative Liabilities
Net Derivative Liabilities Reported in Balance Sheet	130.2	117.7
Offsetting Securities Borrowed
Gross Securities Borrowed	25.8	63.1
Liabilities Offsetting Securities Borrowed in Balance Sheet	0	0
Net Securities Borrowed Reported in Balance Sheet	25.8	63.1
Securities Received as Collateral on Securities Borrowed	(25.8)	(63.1)
Cash Received as Collateral on Securities Borrowed	0	0
Securities Borrowed Net of Collateral	0	0
Offsetting Financial Liabilities
Gross Financial Liability	156	179.3
Financial Assets Offsetting Financial Liabilities in Balance Sheet	0	0
Net Financial Liabilities Reported in Balance Sheet	156	179.3
Securities Given as Collateral on Financial Liabilities	(153.5)	(172.5)
Cash Given as Collateral on Financial Liabilities	0	0
Financial Liabilities Net of Collateral	2.5	6.8
Over the Counter
Offsetting Derivative Assets
Derivative Asset, Fair Value, Gross Asset	105.5	99.9
Derivative Liabilities Offsetting Derivative Assets in Balance Sheet	0	0
Net Derivative Assets Reported in Balance Sheet	105.5	99.9
Securities Received as Collateral on Derivative Assets	(102.9)	(91.9)
Cash Collateral from Counterparties	(2.3)	(6.4)
Derivative Assets Net of Collateral	0.3	1.6
Offsetting Derivative Liabilities
Gross Derivative Liability	130.2	116.2
Derivative Assets Offsetting Derivative Liabilities in Balance Sheet	0	0
Net Derivative Liabilities Reported in Balance Sheet	130.2	116.2
Securities Given as Collateral on Derivative Liabilities	(127.7)	(109.4)
Cash Collateral to counterparties	0	0
Derivative Liabilities Net of Collateral	$ 2.5	$ 6.8

Investments Investment Income (

Investments Investment Income (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net Investment Income
Gross Investment Income, Operating		$ 548.2	$ 542.5	$ 1,643.5	$ 1,619
Less Investment Expenses		17.5	13.5	48.3	44
Less Investment Income on PFA Assets		2.9	3	8.8	9.1
Net Investment Income		527.8	526	1,586.4	1,565.9
Fixed Maturity Securities
Net Investment Income
Gross Investment Income, Operating		465.4	457.9	1,388.5	1,383.7
Derivatives
Net Investment Income
Gross Investment Income, Operating		8.1	11.6	25	34.5
Mortgage Loans
Net Investment Income
Gross Investment Income, Operating		22	22.9	66.6	69.8
Policy Loans
Net Investment Income
Gross Investment Income, Operating		5.7	5.4	16.3	15.6
Perpetual Preferred Securities
Net Investment Income
Gross Investment Income, Operating	[1]	0	0.4	0.3	2.2
Unrealized Gain (Loss) on Investments		0.2	(0.4)		0.1
Private Equity Partnerships
Net Investment Income
Gross Investment Income, Operating	[2]	19.6	22.6	72.6	56.7
Unrealized Gain (Loss) on Investments		25.3	29.7	87.6	72.6
Management Fee Expense		(5.7)	(7.1)	(15)	(15.9)
Other Long-term Investments
Net Investment Income
Gross Investment Income, Operating		3.4	2.6	8.5	7.1
Short-term Investments
Net Investment Income
Gross Investment Income, Operating		$ 24	$ 19.1	$ 65.7	$ 49.4
[1] The net unrealized gain (loss) recognized in net investment income for the three months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was $0.2 million. The net unrealized gain (loss) recognized in net investment income for the nine months ended September 30, 2024 related to perpetual preferred securities still held at September 30, 2024 was de minimis. The net unrealized gain (loss) recognized in net investment income for the three and nine months ended September 30, 2023 related to perpetual preferred securities still held at September 30, 2023 was $(0.4) million and $0.1 million, respectively. 2 The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2024 related to private equity partnerships still held at September 30, 2024 was $25.3 million and $87.6 million, respectively, reduced by net management fees and partnership expenses of $(5.7) million and $(15.0) million, respectively. The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2023 related to private equity partnerships still held at September 30, 2023 was $29.7 million and $72.6 million, respectively, reduced by net management fees and partnership expenses of $(7.1) million and $(15.9) million, respectively. See Note 3 for further discussion of private equity partnerships.

Investment Gains and Losses Rep

Investment Gains and Losses Reported in Consolidated Statements of Income (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fixed Maturity Securities
Gross Gains on Sales	$ 1.1	$ 0.4	$ 1.1	$ 3.7
Gross Losses on Sales	(8.5)	(37.4)	(29.7)	(50.7)
Impairment Loss	(1.3)	0	(2.5)	0
credit losses	(0.2)	0	(3.1)	0
Other Investments
Gross Gains on Sales	0.4	0	9.7	6
Other Investments Gross Realized Losses	0	0.9	0	1
Impairment Loss	0	3	0	3
Current Period Provisions	4.5	(0.9)	6.4	0.9
Embedded Derivative in Modified Coinsurance Arrangement	(0.8)	9.2	6.1	14.7
All Other Derivatives	(2.2)	2	(0.2)	2
Foreign Currency Transactions	3.1	(2.2)	0.5	(0.8)
Net Investment Loss	$ (12.9)	$ (31)	$ (24.5)	$ (30)

Investments - Additional Inform

Investments - Additional Information (Detail)	3 Months Ended			9 Months Ended
	Sep. 30, 2024 USD ($) Integer	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($) Integer	Sep. 30, 2024 USD ($) Integer	Sep. 30, 2023 USD ($) Integer	Dec. 31, 2023 USD ($)
Schedule of Investments
Other Long-term Investments	$ 1,682,800,000			$ 1,682,800,000		$ 1,579,400,000
Accrued Investment Income	$ 786,800,000			786,800,000		633,900,000
Write-offs		$ 0		$ 0
Financing Receivable, Modified, Weighted Average Term Increase from Modification	18 months			18 months
Gains (Losses) on Sales on Loan Foreclosure	$ 0		$ 0	$ 0	$ 0
Commitments to Fund Commercial Mortgage Loans	28,500,000			28,500,000
Real Estate Investment Property, Net	60,800,000			60,800,000		64,400,000
Real Estate Held-for-sale	$ 40,900,000			$ 40,900,000		40,900,000
Repurchase agreements - Typical Days outstanding				30
Minimum percent of the fair value of securities loaned or securities purchased under repurchase agreements be maintained as collateral	102%			102%
Gross Securities Loaned	$ 57,900,000			$ 57,900,000		72,000,000
Outstanding Repurchase Agreements	0			0		0
Off Balance Sheet Amount
Schedule of Investments
Securities Received as Collateral	34,400,000			34,400,000		12,500,000
Cash Collateral for Borrowed Securities	25,800,000			25,800,000		63,100,000
Commercial Real Estate
Schedule of Investments
Financing Receivable, before Allowance for Credit Loss, Mortgage Loans	2,255,400,000			2,255,400,000		2,328,400,000
Financing Receivable, Allowance for Credit Losses, Mortgage Loans	16,500,000			16,500,000		10,200,000
Accrued Investment Income	7,000,000			7,000,000		7,200,000
Financing Receivable, Modified in Period, Amount	14,200,000			14,200,000
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0			0		0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	$ 0		$ 0	$ 0	$ 0
Financing Receivable, Modifications, Number of Contracts | Integer	0		0	0	0
Unfunded Mortgage Loan Commitments
Schedule of Investments
Allowance for Credit Losses, Unfunded Mortgage Loan Commitments	$ 100,000			$ 100,000		0
Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments
Other Long-term Investments	1,428,300,000			1,428,300,000		1,326,500,000
Private Placement Fixed Maturity
Schedule of Investments
Fair Value Disclosure, off-Balance-Sheet Risks, Amount, Liability	38,000,000			38,000,000
Tax Credit Partnership | Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments
Other Long-term Investments	300,000			300,000		300,000
Equity Method Investments | Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments
Other Long-term Investments	$ 1,428,000,000			$ 1,428,000,000		$ 1,326,200,000
External Credit Rating, Investment Grade
Schedule of Investments
Number of Fixed Maturity Securities in an Unrealized Loss Position	835			835
Number of Fixed Maturity Securities in an Unrealized Loss Position Continuously for Over One Year	795			795
External Credit Rating, Below-Investment-Grade
Schedule of Investments
Number of Fixed Maturity Securities in an Unrealized Loss Position	58			58
Number of Fixed Maturity Securities in an Unrealized Loss Position Continuously for Over One Year	50			50

Derivative Financial Instrume_3

Derivative Financial Instruments Nature and Amount of Collateral Received From and Posted To Our Derivative Counterparties (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivative
Derivative Asset, Fair Value, Amount Offset Against Collateral	$ 34.3	$ 37.4
Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	50.6	39.8
Cash
Derivative
Cash Collateral from Counterparties	3.4	11.1
Cash Collateral Posted to Counterparties	0	0
Fixed Maturity Securities
Derivative
Carrying Value of Fixed Maturity Securities Posted as Collateral to Counterparties	30.9	26.3
FMS Collateral Posted to Counterparties	$ 50.6	$ 39.8

Derivative Financial Instrume_4

Derivative Financial Instruments Fair Value Hedges Carrying Amount of Hedged Assets and Liabilities and Cumulative Basis Adjustments (Details) - Interest Rate Swaps - Receive Fixed/Pay Fixed - Designated as Hedging Instrument - Fair Value Hedging - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosures
Hedged Asset, Statement of Financial Position [Extensible Enumeration]	Fixed Maturity Securities - at fair value (amortized cost of $38,822.6; $38,410.6; allowance for credit losses of $2.9; $2.2)	Fixed Maturity Securities - at fair value (amortized cost of $38,822.6; $38,410.6; allowance for credit losses of $2.9; $2.2)
Hedged Asset, Fair Value Hedge	$ 592.9	$ 529.2
Fixed Maturity Securities
Derivative Instruments and Hedging Activities Disclosures
Hedged Asset, Fair Value Hedge, Cumulative Increase	$ (0.5)	$ (6.1)

Location and Fair Values of Der

Location and Fair Values of Derivative Financial Instruments (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivative
Derivative, Notional Amount	$ 3,665.5	$ 2,983.7
Other Long-term Investments
Derivative
Asset Derivatives Fair Value	110.1	99.9
Other Liabilities
Derivative
Liability Derivatives Fair Value	130.2	117.7
Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	3,358.7	2,697
Designated as Hedging Instrument | Cash Flow Hedging
Derivative
Derivative, Notional Amount	2,665.5	2,054.5
Designated as Hedging Instrument | Forwards | Cash Flow Hedging
Derivative
Derivative, Notional Amount	2,523	1,905
Designated as Hedging Instrument | Interest Rate Swaps | Cash Flow Hedging
Derivative
Derivative, Notional Amount	142.5	149.5
Designated as Hedging Instrument | Interest Rate Swaps | Fair Value Hedging
Derivative
Derivative, Notional Amount	693.2	642.5
Designated as Hedging Instrument | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	103.4	96.9
Designated as Hedging Instrument | Other Long-term Investments | Cash Flow Hedging
Derivative
Asset Derivatives Fair Value	62.3	58.7
Designated as Hedging Instrument | Other Long-term Investments | Forwards | Cash Flow Hedging
Derivative
Asset Derivatives Fair Value	47.4	44.5
Designated as Hedging Instrument | Other Long-term Investments | Interest Rate Swaps | Cash Flow Hedging
Derivative
Asset Derivatives Fair Value	14.9	14.2
Designated as Hedging Instrument | Other Long-term Investments | Interest Rate Swaps | Fair Value Hedging
Derivative
Asset Derivatives Fair Value	41.1	38.2
Designated as Hedging Instrument | Other Liabilities
Derivative
Liability Derivatives Fair Value	113.4	99
Designated as Hedging Instrument | Other Liabilities | Cash Flow Hedging
Derivative
Liability Derivatives Fair Value	97.7	82.3
Designated as Hedging Instrument | Other Liabilities | Forwards | Cash Flow Hedging
Derivative
Liability Derivatives Fair Value	94.7	77.8
Designated as Hedging Instrument | Other Liabilities | Interest Rate Swaps | Cash Flow Hedging
Derivative
Liability Derivatives Fair Value	3	4.5
Designated as Hedging Instrument | Other Liabilities | Interest Rate Swaps | Fair Value Hedging
Derivative
Liability Derivatives Fair Value	15.7	16.7
Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	306.8	286.7
Not Designated as Hedging Instrument | Forwards
Derivative
Derivative, Notional Amount	54.6	52.5
Not Designated as Hedging Instrument | Interest Rate Swaps
Derivative
Derivative, Notional Amount	125.9	132
Not Designated as Hedging Instrument | Total Return Swap
Derivative
Derivative, Notional Amount	126.3	102.2
Not Designated as Hedging Instrument | Embedded Derivative in Modified Coinsurance Arrangement
Derivative
Derivative, Notional Amount	0	0
Not Designated as Hedging Instrument | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	6.7	3
Not Designated as Hedging Instrument | Other Long-term Investments | Forwards
Derivative
Asset Derivatives Fair Value	2.1	3
Not Designated as Hedging Instrument | Other Long-term Investments | Interest Rate Swaps
Derivative
Asset Derivatives Fair Value	0	0
Not Designated as Hedging Instrument | Other Long-term Investments | Total Return Swap
Derivative
Asset Derivatives Fair Value	0	0
Not Designated as Hedging Instrument | Other Long-term Investments | Embedded Derivative in Modified Coinsurance Arrangement
Derivative
Asset Derivatives Fair Value	4.6	0
Not Designated as Hedging Instrument | Other Liabilities
Derivative
Liability Derivatives Fair Value	16.8	18.7
Not Designated as Hedging Instrument | Other Liabilities | Forwards
Derivative
Liability Derivatives Fair Value	0.5	0.2
Not Designated as Hedging Instrument | Other Liabilities | Interest Rate Swaps
Derivative
Liability Derivatives Fair Value	16.3	17
Not Designated as Hedging Instrument | Other Liabilities | Total Return Swap
Derivative
Liability Derivatives Fair Value	0	0
Not Designated as Hedging Instrument | Other Liabilities | Embedded Derivative in Modified Coinsurance Arrangement
Derivative
Liability Derivatives Fair Value	$ 0	$ 1.5

Derivative Financial Instrume_5

Derivative Financial Instruments Location of Gains and Losses Designated as Hedging Instruments, Consolidated Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments, Gain (Loss)
Net Investment Income	$ 527.8	$ 526	$ 1,586.4	$ 1,565.9
Net Investment Gain (Loss)	(12.9)	(31)	(24.5)	(30)
Interest and Debt Expense	49.2	48.6	148.6	145.6
Net Gain (Loss) on Derivatives	(2.2)	2	(0.2)	2
Designated as Hedging Instrument | Interest Rate Swaps | Net Investment Income | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	21.1	49.7	91.3	148.2
Net Gain (Loss) on Derivatives	3.7	8.3	14.5	27.7
Designated as Hedging Instrument | Interest Rate Swaps | Net Investment Gain (Loss) | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	0	0	0	0.8
Net Gain (Loss) on Derivatives	0	0	0	0
Designated as Hedging Instrument | Interest Rate Swaps | Interest and Debt Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	0.7	0.7	2.2	2.2
Net Gain (Loss) on Derivatives	0	0	0	0
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Investment Income | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	2.3	2.3	6.5	7.3
Net Gain (Loss) on Derivatives	0.9	0.4	0.5	0.6
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Investment Income | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	4.9	3.9	13.4	10.3
Net Gain (Loss) on Derivatives	4.2	3.1	11.5	6.7
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Investment Gain (Loss) | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	(0.7)	(0.1)	(0.4)	(0.1)
Net Gain (Loss) on Derivatives	0.7	0	0.5	0.1
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Investment Gain (Loss) | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	25.2	(15.2)	5.6	(8.7)
Net Gain (Loss) on Derivatives	(25.2)	15.2	(5.6)	8.7
Designated as Hedging Instrument | Foreign Exchange Contracts | Interest and Debt Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	0	0	0	0
Net Gain (Loss) on Derivatives	0	0	0	0
Designated as Hedging Instrument | Foreign Exchange Contracts | Interest and Debt Expense | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	0	0	0	0
Net Gain (Loss) on Derivatives	0	0	0	0
Designated as Hedging Instrument | Forwards | Net Investment Income | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	10.7	3.9	29.6	7.7
Net Gain (Loss) on Derivatives	(0.3)	(0.1)	(0.7)	(0.1)
Designated as Hedging Instrument | Forwards | Net Investment Gain (Loss) | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	0	0	0	0
Net Gain (Loss) on Derivatives	0	0	0	0
Designated as Hedging Instrument | Forwards | Interest and Debt Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	0	0	0	0
Net Gain (Loss) on Derivatives	$ 0	$ 0	$ 0	$ 0

Location of Gains and Losses on

Location of Gains and Losses on Derivative Instruments Designated as Cash Flow Hedging Instruments (Detail) - Designated as Hedging Instrument - Cash Flow Hedging - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments, Gain (Loss)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ 64.8	$ (155.5)	$ (37)	$ (159)
Forwards
Derivative Instruments, Gain (Loss)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	66	(158.9)	(39.6)	(159.7)
Foreign Exchange Contracts
Derivative Instruments, Gain (Loss)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ (1.2)	$ 3.4	$ 2.6	$ 0.7

Gains and Losses on Derivatives

Gains and Losses on Derivatives Not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	$ (2.2)	$ 2	$ (0.2)	$ 2
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	(3)	11.2	5.9	16.7
Foreign Exchange Contracts | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	(2.2)	2	(0.2)	2
Embedded Derivative in Modified Coinsurance Arrangement | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	(0.8)	9.2	6.1	14.7
Total Return Swap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	$ (5.4)	$ 4.1	$ (14.1)	$ (4.7)

Derivative Financial Instrume_6

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Derivative
Credit Exposure on Derivatives	$ 0.3		$ 0.3		$ 1.6
Aggregate fair value of all derivative instruments with credit risk-related contingent features in a liability position	130.2		130.2		116.2
Derivative, Notional Amount	3,665.5		3,665.5		2,983.7
Approximate amount of net deferred gains on derivative instruments expected to be amortized during the next twelve months			9.2
Component of Derivative Gain (Loss) Excluded from the Assessment of Hedge Effectiveness	8.2	$ (19.4)	9.5	$ (26.6)
Discontinued Hedge Accounting Due to Instrument No Longer Qualifying as Fair Value Hedge	0	$ 0	$ 0	$ 0
Maximum Length of Time Hedged in Cash Flow Hedge			39 years
Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	3,358.7		$ 3,358.7		2,697
Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	306.8		306.8		286.7
Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	2,665.5		2,665.5		2,054.5
Interest Rate Swaps | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	125.9		125.9		132
Interest Rate Swaps | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	142.5		142.5		149.5
Interest Rate Swaps | Fair Value Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	693.2		693.2		642.5
Forwards | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	54.6		54.6		52.5
Forwards | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	2,523		2,523		1,905
Total Return Swap | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	126.3		126.3		102.2
Embedded Derivative in Modified Coinsurance Arrangement | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	0		0		0
Receive Fixed/Pay Fixed | Interest Rate Swaps | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	125.9		125.9		132
Receive Fixed/Pay Fixed | Interest Rate Swaps | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	142.5		142.5		149.5
Receive Fixed/Pay Fixed | Interest Rate Swaps | Fair Value Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	$ 693.2		$ 693.2		$ 642.5

Schedule of Accumulated Other C

Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	$ (2,846.2)	$ (3,457.6)	$ (3,308)	$ (3,448.3)
Other Comprehensive Income (Loss) Before Reclassifications	109.6	282.8	552.8	278
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	6.9	24.2	25.5	19.7
Net Other Comprehensive Income	116.5	307	578.3	297.7
Balance at End of Period	(2,729.7)	(3,150.6)	(2,729.7)	(3,150.6)
Net Unrealized Loss on Securities
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(2,723.8)	(2,762.6)	(1,919.1)	(3,028.4)
Other Comprehensive Income (Loss) Before Reclassifications	1,225.8	(1,215.1)	401.1	(957.2)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	6.8	29.3	26.8	37.2
Net Other Comprehensive Income	1,232.6	(1,185.8)	427.9	(920)
Balance at End of Period	(1,491.2)	(3,948.4)	(1,491.2)	(3,948.4)
Effect of Change in Discount Rate Assumptions on the LFPB
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	712.3	0.1	(648.4)	313.9
Other Comprehensive Income (Loss) Before Reclassifications	(1,239.3)	1,688.4	121.4	1,374.6
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	0	0	0	0
Net Other Comprehensive Income	(1,239.3)	1,688.4	121.4	1,374.6
Balance at End of Period	(527)	1,688.5	(527)	1,688.5
Net Loss on Derivatives
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(164.6)	(33.3)	(73.7)	(9.6)
Other Comprehensive Income (Loss) Before Reclassifications	58.8	(137.9)	(24.3)	(146.4)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	(3.1)	(6.5)	(10.9)	(21.7)
Net Other Comprehensive Income	55.7	(144.4)	(35.2)	(168.1)
Balance at End of Period	(108.9)	(177.7)	(108.9)	(177.7)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(328.4)	(327.1)	(321.1)	(390.1)
Other Comprehensive Income (Loss) Before Reclassifications	68.5	(55.1)	61.2	7.9
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	0	0	0	0
Net Other Comprehensive Income	68.5	(55.1)	61.2	7.9
Balance at End of Period	(259.9)	(382.2)	(259.9)	(382.2)
Unrecognized Pension and Postretirement Benefit Costs
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Period	(341.7)	(334.7)	(345.7)	(334.1)
Other Comprehensive Income (Loss) Before Reclassifications	(4.2)	2.5	(6.6)	(0.9)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	3.2	1.4	9.6	4.2
Net Other Comprehensive Income	(1)	3.9	3	3.3
Balance at End of Period	$ (342.7)	$ (330.8)	$ (342.7)	$ (330.8)

Schedule of Reclassifications O

Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Loss	$ (12.9)	$ (31)	$ (24.5)	$ (30)
Impairment Loss	(1.3)	0	(2.5)	0
credit losses	0.2	0	3.1	0
Net Investment Income	527.8	526	1,586.4	1,565.9
Other Expenses	311.5	271.8	903.3	818.6
Income Tax Expense (Benefit)	168.9	59.7	375.4	258.2
Net Income	645.7	202	1,430.4	953.2
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Net Unrealized Loss on Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Loss	(7.4)	(37)	(28.6)	(47)
Impairment Loss	(1.3)	0	(2.5)	0
credit losses	(0.2)	0	(3.1)	0
Income Before Income Tax	(8.9)	(37)	(34.2)	(47)
Income Tax Expense (Benefit)	(2.1)	(7.7)	(7.4)	(9.8)
Net Income	(6.8)	(29.3)	(26.8)	(37.2)
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Net Loss on Derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Income Before Income Tax	4	8.2	13.8	27.5
Income Tax Expense (Benefit)	0.9	1.7	2.9	5.8
Net Income	(3.1)	(6.5)	(10.9)	(21.7)
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Net Loss on Derivatives | Interest Rate Swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Income	3.4	8.3	13.8	27.6
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Net Loss on Derivatives | Foreign Exchange Contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Loss	0.6	0	0.1	0.1
Net Investment Income	0	(0.1)	(0.1)	(0.2)
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Amortization of Net Actuarial Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other Expenses	4.2	1.8	12.4	5.4
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other Expenses	0.1	0	0.2	0.1
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Unrecognized Pension and Postretirement Benefit Costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Income Before Income Tax	(4.1)	(1.8)	(12.2)	(5.3)
Income Tax Expense (Benefit)	(0.9)	(0.4)	(2.6)	(1.1)
Net Income	$ (3.2)	$ (1.4)	$ (9.6)	$ (4.2)

Liability for Future Policy B_3

Liability for Future Policy Benefit Activity (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2024		Sep. 30, 2023		Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Future Policy Benefits		$ 39,444.5				$ 40,009.4
Operating Segments
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		14,417.8		$ 12,426.2
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		14,243.2		12,695.3
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						73	$ 1,499.2
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(151.9)	(121.8)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						14,164.3	14,072.7
Liability for Future Policy Benefit, Expected Net Premium, Issuance		856.7		861.2
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		481.8		430.8
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(1,222.6)		(1,164.9)
Liability for Future Policy Benefit, Expected Net Premium, Increase (Decrease) for Other Change		7.3		(0.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		14,287.5		14,199.7
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		319		(709)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		14,606.5		13,490.7
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		52,423.6		48,929.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		51,305.7		49,689
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(248.5)	1,702
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(355.6)	(356.4)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						$ 50,701.6	$ 51,034.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance	[1]	2,506.9		2,547
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		1,707.3		1,670.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(4,078.4)		(4,106.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Increase (Decrease) for Other Change		121		19.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		50,958.4		51,165.4
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		1,204.1		(3,111.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		52,162.5		48,053.7
Liability for Future Policy Benefit, before Reinsurance, before Other		37,556		34,563
Liability for Future Policy Benefit, Other		1,655.7		1,703.3
Liability for Future Policy Benefit, before Reinsurance, after Other		39,211.7		36,266.3
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		7,455.9		7,449
Liability for Future Policy Benefit, after Reinsurance		31,755.8		28,817.3
Liability for Future Policy Benefit, Gross Premium Income		7,568.4		7,278.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		1,225.5		1,239.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		104,039.1		105,306.1
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		39,394.1		38,581.4
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 25,941.4		$ 25,435.2
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.90%		4.80%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.80%		5.60%		4.80%	5%
Liability for Future Policy Benefit, Weighted-Average Duration		11 years 6 months		11 years 6 months
Future Policy Benefits		$ 39,444.5		$ 36,502.4
Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		2,431.4		2,071.1
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		2,486.9		2,166
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						$ (58.7)	$ 185.7
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(77.4)	(111.8)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						2,350.8	2,239.9
Liability for Future Policy Benefit, Expected Net Premium, Issuance		414.2		422.6
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		69.7		57.7
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(283.6)		(255.9)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		2,551.1		2,464.3
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(25)		(181.6)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		2,526.1		2,282.7
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		11,752.5		11,698.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		11,949.5		12,177.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(197.2)	77.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(302.1)	(367.9)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						11,450.2	11,887.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		1,669.2		1,707.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		322.5		340.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(1,845)		(1,936.3)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		11,596.9		11,999.2
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(75.6)		(816.4)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		11,521.3		11,182.8
Liability for Future Policy Benefit, before Reinsurance, before Other		8,995.2		8,900.1
Liability for Future Policy Benefit, Other		31.7		29.9
Liability for Future Policy Benefit, before Reinsurance, after Other		9,026.9		8,930
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		200.8		200.3
Liability for Future Policy Benefit, after Reinsurance		8,826.1		8,729.7
Liability for Future Policy Benefit, Gross Premium Income		4,906.6		4,679.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		252.8		283.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		17,640.3		17,943.5
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		11,639.4		11,019.3
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,034.8		$ 7,763.3
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.30%		4.20%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.30%		5.30%
Liability for Future Policy Benefit, Weighted-Average Duration		7 years 1 month 6 days		6 years 10 months 24 days
Future Policy Benefits	[2]	$ 9,026.9		$ 8,930
Unum International
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		270.3		197.1
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		298.4		246.8
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						(5.9)	(5.1)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						15.1	12.2
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						307.6	253.9
Liability for Future Policy Benefit, Expected Net Premium, Issuance		25.3		16.9
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		8.7		6.9
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(21.2)		(16.9)
Liability for Future Policy Benefit, Expected Net Premium, Increase (Decrease) for Other Change		7.3		(0.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		327.7		260.7
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(27.9)		(37.6)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		299.8		223.1
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		2,527.4		2,231.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		2,687.1		2,495.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						0.1	17.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(13.4)	(9.2)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						2,673.8	2,504
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance	[3]	300.3		277.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		51.3		47.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(326.4)		(307.5)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Increase (Decrease) for Other Change		121		19.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		2,820		2,541.1
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(214.9)		(297.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		2,605.1		2,244
Liability for Future Policy Benefit, before Reinsurance, before Other		2,305.3		2,020.9
Liability for Future Policy Benefit, Other		43.1		30.3
Liability for Future Policy Benefit, before Reinsurance, after Other		2,348.4		2,051.2
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		78		69.4
Liability for Future Policy Benefit, after Reinsurance		2,270.4		1,981.8
Liability for Future Policy Benefit, Gross Premium Income		710.2		667.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		42.6		40.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		4,536.2		4,012.8
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		1,335.6		1,035.7
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 854.1		$ 676.8
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.10%		4%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.90%		5.40%
Liability for Future Policy Benefit, Weighted-Average Duration		8 years 10 months 24 days		8 years 7 months 6 days
Future Policy Benefits		$ 2,348.4		$ 2,051.2
Colonial Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		3,592.6		3,745.4
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		3,754.3		4,046.4
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change		(7.9)		(322.7)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(57)	(77.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						3,689.4	3,646.6
Liability for Future Policy Benefit, Expected Net Premium, Issuance		417.2		421.7
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		101.4		94.3
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(455.5)		(454)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		3,752.5		3,708.6
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(105.6)		(348.7)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		3,646.9		3,359.9
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		5,566		5,581.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		5,925.2		6,163.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change		(52.7)		(402.9)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(84.2)	(90.1)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						5,788.3	5,670.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		455.1		461.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		172.2		161
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(458.4)		(462.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		5,957.2		5,830.9
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(303.5)		(731.9)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		5,653.7		5,099
Liability for Future Policy Benefit, before Reinsurance, before Other		2,006.8		1,739.1
Liability for Future Policy Benefit, Other		25.1		24.3
Liability for Future Policy Benefit, before Reinsurance, after Other		2,031.9		1,763.4
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		1.5		0.9
Liability for Future Policy Benefit, after Reinsurance		2,030.4		1,762.5
Liability for Future Policy Benefit, Gross Premium Income		1,286.4		1,240.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		70.8		66.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		10,242.2		9,568.2
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		12,450.4		11,847.5
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,948.9		$ 8,684.1
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.40%		4.30%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.80%		5.70%
Liability for Future Policy Benefit, Weighted-Average Duration		17 years 3 months 18 days		16 years 10 months 24 days
Future Policy Benefits		$ 2,031.9		$ 1,763.4
Closed Block
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		8,123.5		6,412.6
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		7,703.6		6,236.1
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						145.5	1,641.3
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(32.6)	54.9
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						7,816.5	7,932.3
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		302		271.9
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(462.3)		(438.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		7,656.2		7,766.1
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		477.5		(141.1)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		8,133.7		7,625
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		32,577.7		29,418.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		30,743.9		28,852.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						1.3	2,009.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						44.1	110.8
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						30,789.3	30,972.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		82.3		101.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		1,161.3		1,120.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(1,448.6)		(1,400.2)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		30,584.3		30,794.2
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		1,798.1		(1,266.3)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		32,382.4		29,527.9
Liability for Future Policy Benefit, before Reinsurance, before Other		24,248.7		21,902.9
Liability for Future Policy Benefit, Other		1,555.8		1,618.8
Liability for Future Policy Benefit, before Reinsurance, after Other		25,804.5		23,521.7
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		7,175.6		7,178.3
Liability for Future Policy Benefit, after Reinsurance		18,628.9		16,343.4
Liability for Future Policy Benefit, Gross Premium Income		665.2		690.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		859.3		848.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		71,620.4		73,781.6
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		13,968.7		14,678.9
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,103.6		$ 8,311
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.20%		5.20%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.90%		5.80%
Liability for Future Policy Benefit, Weighted-Average Duration		13 years		13 years 3 months 18 days
Future Policy Benefits	[2]	$ 25,804.5		$ 23,521.7
Other Products [Member]
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Future Policy Benefits	[2]	232.8		236.1
Group Disability | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		0		0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		0		0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						0	0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						0	0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						0	0
Liability for Future Policy Benefit, Expected Net Premium, Issuance		0		0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		0		0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		0		0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		0		0
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		0		0
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		0		0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		5,147.4		5,533.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		5,277.1		5,793.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(76.4)	(100.2)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(152.4)	(187.8)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						5,048.3	5,505.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		893.7	[4]	907.1	[5]
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		121.7		137.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(1,109.7)		(1,186.8)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		4,954		5,363
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(43.4)		(310.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		4,910.6		5,052.9
Liability for Future Policy Benefit, before Reinsurance, before Other		4,910.6		5,052.9
Liability for Future Policy Benefit, Other		0.1		0.5
Liability for Future Policy Benefit, before Reinsurance, after Other		4,910.7		5,053.4
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		26.8		32.8
Liability for Future Policy Benefit, after Reinsurance		4,883.9		5,020.6
Liability for Future Policy Benefit, Gross Premium Income		2,294.8		2,210.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		121.7		137.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		6,001.5		6,474.2
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		0		0
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 0		$ 0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.10%		4%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.30%		5.40%
Liability for Future Policy Benefit, Weighted-Average Duration		4 years 2 months 12 days		4 years 3 months 18 days
Group Life and AD&D | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 0		$ 0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		0		0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						0	0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						0	0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						0	0
Liability for Future Policy Benefit, Expected Net Premium, Issuance		0		0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		0		0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		0		0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		0		0
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		0		0
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		0		0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		922		972.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		936.5		998.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(17)	0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(49.7)	(28.2)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						869.8	970.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		333.3	[4]	356.1	[5]
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		14.3		15.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(357.8)		(402.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		859.6		940.1
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(6.3)		(35.6)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		853.3		904.5
Liability for Future Policy Benefit, before Reinsurance, before Other		853.3		904.5
Liability for Future Policy Benefit, Other		0.8		1
Liability for Future Policy Benefit, before Reinsurance, after Other		854.1		905.5
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		5.7		6.2
Liability for Future Policy Benefit, after Reinsurance		848.4		899.3
Liability for Future Policy Benefit, Gross Premium Income		1,496.3		1,403.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		14.3		15.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		977		1,069.2
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		0		0
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 0		$ 0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		2.30%		2.30%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		2.40%		3.10%
Liability for Future Policy Benefit, Weighted-Average Duration		2 years 6 months		2 years 8 months 12 days
Individual Disability | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 1,296.7		$ 1,202.9
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		1,294.4		1,228.1
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						(100.2)	5
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(5.3)	(13.6)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						1,188.9	1,219.5
Liability for Future Policy Benefit, Expected Net Premium, Issuance		119.2		164
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		39.8		36.3
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(138.7)		(131.7)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		1,209.2		1,288.1
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		16.7		(62.2)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		1,225.9		1,225.9
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		3,348.6		3,192.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		3,313.9		3,244.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(155.4)	7.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(18.9)	(42.3)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						3,139.6	3,210.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		127.1		173.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		113.3		123.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(207.2)		(203.5)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		3,172.8		3,303.6
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		65.8		(190)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		3,238.6		3,113.6
Liability for Future Policy Benefit, before Reinsurance, before Other		2,012.7		1,887.7
Liability for Future Policy Benefit, Other		28.1		26
Liability for Future Policy Benefit, before Reinsurance, after Other		2,040.8		1,913.7
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		154.6		148.1
Liability for Future Policy Benefit, after Reinsurance		1,886.2		1,765.6
Liability for Future Policy Benefit, Gross Premium Income		494.2		474.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		73.5		86.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		5,082.2		5,292.7
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		5,817		5,701.8
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 4,180.2		$ 4,099.5
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.10%		5.10%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.60%		5.70%
Liability for Future Policy Benefit, Weighted-Average Duration		9 years 4 months 24 days		9 years 7 months 6 days
Voluntary Benefits | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 1,134.7		$ 868.2
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		1,192.5		937.9
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						41.5	180.7
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(72.1)	(98.2)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						1,161.9	1,020.4
Liability for Future Policy Benefit, Expected Net Premium, Issuance		295		258.6
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		29.9		21.4
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(144.9)		(124.2)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		1,341.9		1,176.2
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(41.7)		(119.4)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		1,300.2		1,056.8
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		2,334.5		1,999.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		2,422		2,141.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						51.6	170.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(81.1)	(109.6)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						2,392.5	2,201.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		315.1		270.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		73.2		64.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(170.3)		(143.9)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		2,610.5		2,392.5
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(91.7)		(280.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		2,518.8		2,111.8
Liability for Future Policy Benefit, before Reinsurance, before Other		1,218.6		1,055
Liability for Future Policy Benefit, Other		2.7		2.4
Liability for Future Policy Benefit, before Reinsurance, after Other		1,221.3		1,057.4
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		13.7		13.2
Liability for Future Policy Benefit, after Reinsurance		1,207.6		1,044.2
Liability for Future Policy Benefit, Gross Premium Income		621.3		592.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		43.3		42.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		5,579.6		5,107.4
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		5,822.4		5,317.5
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 3,854.6		$ 3,663.8
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5%		5%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.90%		5.70%
Liability for Future Policy Benefit, Weighted-Average Duration		18 years 6 months		18 years 2 months 12 days
Other Insurance Product Line | Closed Block
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 0		$ 0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		0		0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						0	0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						0	0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						0	0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		0		0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		0		0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		0		0
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		0		0
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		0		0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		7,880		8,218.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		8,094.6		8,630.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						5.4	0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						5.2	4.1
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						8,105.2	8,634.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		82.3	[6]	101.2	[7]
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		261.6		270
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(738.6)		(776)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		7,710.5		8,230
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(129.2)		(687)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		7,581.3		7,543
Liability for Future Policy Benefit, before Reinsurance, before Other		7,581.3		7,543
Liability for Future Policy Benefit, Other		1,556.5	[8]	1,606	[9]
Liability for Future Policy Benefit, before Reinsurance, after Other		9,137.8		9,149
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		7,171.4		7,173.7
Liability for Future Policy Benefit, after Reinsurance		1,966.4		1,975.3
Liability for Future Policy Benefit, Gross Premium Income		143.6		169.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		261.6		270
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		11,281.4		12,109.6
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		0		0
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 0		$ 0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.60%		4.60%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		4.70%		5.70%
Liability for Future Policy Benefit, Weighted-Average Duration		7 years 2 months 12 days		7 years 3 months 18 days
Long-term Care | Closed Block
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 8,123.5		$ 6,412.6
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		7,703.6		6,236.1
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						145.5	1,641.3
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(32.6)	54.9
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						7,816.5	7,932.3
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		302		271.9
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(462.3)		(438.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		7,656.2		7,766.1
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		477.5		(141.1)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		8,133.7		7,625
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		24,697.7		21,199.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		22,649.3		20,221.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(4.1)	2,009.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						38.9	106.7
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						$ 22,684.1	$ 22,337.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		0		0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		899.7		850.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(710)		(624.2)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		22,873.8		22,564.2
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		1,927.3		(579.3)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		24,801.1		21,984.9
Liability for Future Policy Benefit, before Reinsurance, before Other		16,667.4		14,359.9
Liability for Future Policy Benefit, Other		(0.7)		12.8
Liability for Future Policy Benefit, before Reinsurance, after Other		16,666.7		14,372.7
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		4.2		4.6
Liability for Future Policy Benefit, after Reinsurance		16,662.5		14,368.1
Liability for Future Policy Benefit, Gross Premium Income		521.6		521.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		597.7		578.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		60,339		61,672
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		13,968.7		14,678.9
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,103.6		$ 8,311
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.60%		5.60%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5%		5.80%
Liability for Future Policy Benefit, Weighted-Average Duration		15 years 10 months 24 days		16 years 7 months 6 days
Liability for Future Policy Benefit, Adverse Development, Expense		$ 70.8		$ (215.5)
[1] 1 Issuances include new policy issuances for most product lines. For our Unum US group disability, Unum US group life and AD&D and Closed Block - All Other product lines and certain of our Unum International product lines, this line represents new claim incurrals. 1 1 Issuances for Unum International primarily represent new claim incurrals. 1 Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals. 1 Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals. 1 Issuances for Closed Block - All Other represents new claim incurrals. 1 Issuances for Closed Block - All Other represents new claim incurrals. 2 Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products. 2 Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products.

Policyholder Account Balance (D

Policyholder Account Balance (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024		Sep. 30, 2023		Dec. 31, 2023
Policyholder Account Balance [Roll Forward]
Policyholders' Account Balances	$ 5,661.3				$ 5,667.7
Operating Segments
Policyholder Account Balance [Roll Forward]
Policyholder Account Balance, before Reserves in excess of Account Balance, Beginning of Year	5,514.2		$ 5,598.6
Policyholder Account Balance, Premium Received	124.2		134.5
Policyholder Account Balance, Policy Charge	(170.8)	[1]	(181)	[2]
Policyholder Account Balance, Surrender and Withdrawal	(64.5)		(64.2)
Policyholder Account Balance, Benefit Payment	(167.9)		(204.1)
Policyholder Account Balance, Interest Expense	261.4		281.7
Policyholder Account Balance, Increase (Decrease) from Other Change	8.6		30.8
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	5,505.2		5,596.3
Policyholder Account Balance, Reserves in excess of Account Balance	156.1		148.2
Policyholders' Account Balances	5,661.3		5,744.5
Policyholder Account Balance, Reinsurance recoverable	4,124.3		4,199.3
Policyholder Account Balance, After reinsurance recoverable	$ 1,537		$ 1,545.2
Policyholder Account Balance, Weighted Average Crediting Rate	6.50%		6.90%
Policyholder Account Balance, Net Amount at Risk	$ 14,234.1	[3]	$ 15,308.7	[4]
Policyholder Account Balance, Cash Surrender Value	5,440.2		5,412.4
Unum US | Voluntary Benefits
Policyholder Account Balance [Roll Forward]
Policyholder Account Balance, before Reserves in excess of Account Balance, Beginning of Year	578.6		586.8
Policyholder Account Balance, Premium Received	40.7		44.9
Policyholder Account Balance, Policy Charge	(42.9)	[1]	(45.8)	[2]
Policyholder Account Balance, Surrender and Withdrawal	(24.3)		(23.6)
Policyholder Account Balance, Benefit Payment	(4.8)		(7.5)
Policyholder Account Balance, Interest Expense	15.7		17
Policyholder Account Balance, Increase (Decrease) from Other Change	7.6		6.7
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	570.6		578.5
Policyholder Account Balance, Reserves in excess of Account Balance	104.4		99.2
Policyholders' Account Balances	675		677.7
Policyholder Account Balance, Reinsurance recoverable	0.8		1
Policyholder Account Balance, After reinsurance recoverable	$ 674.2		$ 676.7
Policyholder Account Balance, Weighted Average Crediting Rate	3.70%		4%
Policyholder Account Balance, Net Amount at Risk	$ 4,210.4	[3]	$ 4,600	[4]
Policyholder Account Balance, Cash Surrender Value	560.4		568.9
Colonial Life
Policyholder Account Balance [Roll Forward]
Policyholder Account Balance, before Reserves in excess of Account Balance, Beginning of Year	852.9		852.4
Policyholder Account Balance, Premium Received	60.2		64.4
Policyholder Account Balance, Policy Charge	(54.2)	[1]	(56.3)	[2]
Policyholder Account Balance, Surrender and Withdrawal	(30.4)		(28.5)
Policyholder Account Balance, Benefit Payment	(6)		(5.6)
Policyholder Account Balance, Interest Expense	25.6		25.7
Policyholder Account Balance, Increase (Decrease) from Other Change	0.2		(0.2)
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	848.3		851.9
Policyholder Account Balance, Reserves in excess of Account Balance	14.5		16.6
Policyholders' Account Balances	862.8		868.5
Policyholder Account Balance, Reinsurance recoverable	0		0
Policyholder Account Balance, After reinsurance recoverable	$ 862.8		$ 868.5
Policyholder Account Balance, Weighted Average Crediting Rate	4.10%		4.10%
Policyholder Account Balance, Net Amount at Risk	$ 8,325	[3]	$ 8,901.6	[4]
Policyholder Account Balance, Cash Surrender Value	817.1		810.1
Closed Block | Other Insurance Product Line
Policyholder Account Balance [Roll Forward]
Policyholder Account Balance, before Reserves in excess of Account Balance, Beginning of Year	4,082.7		4,159.4
Policyholder Account Balance, Premium Received	23.3		25.2
Policyholder Account Balance, Policy Charge	(73.7)	[1]	(78.9)	[2]
Policyholder Account Balance, Surrender and Withdrawal	(9.8)		(12.1)
Policyholder Account Balance, Benefit Payment	(157.1)		(191)
Policyholder Account Balance, Interest Expense	220.1		239
Policyholder Account Balance, Increase (Decrease) from Other Change	0.8		24.3
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	4,086.3		4,165.9
Policyholder Account Balance, Reserves in excess of Account Balance	37.2		32.4
Policyholders' Account Balances	4,123.5		4,198.3
Policyholder Account Balance, Reinsurance recoverable	4,123.5		4,198.3
Policyholder Account Balance, After reinsurance recoverable	$ 0		$ 0
Policyholder Account Balance, Weighted Average Crediting Rate	7.40%		8%
Policyholder Account Balance, Net Amount at Risk	$ 1,698.7	[3]	$ 1,807.1	[4]
Policyholder Account Balance, Cash Surrender Value	$ 4,062.7		$ 4,033.4
[1] 1 Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance. 1 Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance. 2 For those guarantees of benefits that are payable in the event of death, the net amount at risk is generally defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date. 2 For those guarantees of benefits that are payable in the event of death, the net amount at risk is generally defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date.

Policyholder Account Balance, G

Policyholder Account Balance, Guaranteed Minimum Crediting (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	$ 5,505.2	$ 5,514.2	$ 5,596.3	$ 5,598.6
Policyholder Account Balance, Guaranteed Minimum Credit Rating | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	1,600.4		2,067.6
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	3,841.3		3,501.6
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	63.5		27.1
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Colonial Life
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	848.3	852.9	851.9	852.4
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	848.3		851.9
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	842		845.8
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	6.3		6.1
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	4,086.3	4,082.7	4,165.9	4,159.4
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	417.2		831.8
Other Insurance Product Line | Closed Block | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	3,641.4		3,307
Other Insurance Product Line | Closed Block | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	27.7		27.1
Other Insurance Product Line | Closed Block | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	1,560.7		1,639.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	415.9		431.3
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	1,117.1		1,181.2
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	27.7		27.1
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	26.9		30.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	1.3		2.1
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	25.6		28.5
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	2,299.3		2,313.1
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		398.4
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	2,299.3		1,914.7
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	199.4		182.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	199.4		182.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	570.6	$ 578.6	578.5	$ 586.8
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	341.2		390
Voluntary Benefits | Unum US | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	193.6		188.5
Voluntary Benefits | Unum US | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	35.8		0
Voluntary Benefits | Unum US | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	89.8		91.6
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	89.8		91.6
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	449.6		453.9
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	220.2		265.4
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	193.6		188.5
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	35.8		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	31.2		33
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	31.2		33
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0		0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	$ 0		$ 0
Minimum | Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4%		4%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3%		3%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	6%		6%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	9%		9%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	12%		12%
Minimum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3%		3%
Minimum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4%		4%
Minimum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	5%		5%
Maximum | Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	5%		5%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	5.99%		5.99%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	8.99%		8.99%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	11.99%		11.99%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	15%		15%
Maximum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3.99%		3.99%
Maximum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4.99%		4.99%
Maximum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	6%		6%

Deferred Policy Acquisition Cos

Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			$ 2,714.5
Deferred Policy Acquisition Costs, Amortization Expense	$ (133.8)	$ (129.1)	(387.9)	$ (358.7)
Deferred Acquisition Costs at End of Period	2,823.5		2,823.5
Operating Segments
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			2,714.5	2,560
Deferred Policy Acquisition Cost			495.3	467.5
Deferred Policy Acquisition Costs, Amortization Expense			(387.9)	(358.7)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment and Other			1.6	(0.1)
Deferred Acquisition Costs at End of Period	2,823.5	2,668.7	2,823.5	2,668.7
Unum US
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			1,232.2	1,185.1
Deferred Policy Acquisition Cost			247.4	230.6
Deferred Policy Acquisition Costs, Amortization Expense			(216.7)	(199.2)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment and Other			0	0
Deferred Acquisition Costs at End of Period	1,262.9	1,216.5	1,262.9	1,216.5
Unum US | Group Disability
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			63.6	61
Deferred Policy Acquisition Cost			48.1	44.7
Deferred Policy Acquisition Costs, Amortization Expense			(46.8)	(42.1)
Deferred Acquisition Costs at End of Period	64.9	63.6	64.9	63.6
Unum US | Group Life and AD&D
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			48.9	49.3
Deferred Policy Acquisition Cost			31	28.9
Deferred Policy Acquisition Costs, Amortization Expense			(26.7)	(29.5)
Deferred Acquisition Costs at End of Period	53.2	48.7	53.2	48.7
Unum US | Voluntary Benefits
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			610.6	601
Deferred Policy Acquisition Cost			93.2	85.2
Deferred Policy Acquisition Costs, Amortization Expense			(88.4)	(79.5)
Deferred Acquisition Costs at End of Period	615.4	606.7	615.4	606.7
Unum US | Individual Disability
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			497.8	464.4
Deferred Policy Acquisition Cost			63.9	62.6
Deferred Policy Acquisition Costs, Amortization Expense			(45.3)	(40.2)
Deferred Acquisition Costs at End of Period	516.4	486.8	516.4	486.8
Unum US | Dental and Vision
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			11.3	9.4
Deferred Policy Acquisition Cost			11.2	9.2
Deferred Policy Acquisition Costs, Amortization Expense			(9.5)	(7.9)
Deferred Acquisition Costs at End of Period	13	10.7	13	10.7
Unum International
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			46.9	37
Deferred Policy Acquisition Cost			13.2	10.8
Deferred Policy Acquisition Costs, Amortization Expense			(7.3)	(6.1)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment and Other			1.6	(0.1)
Deferred Acquisition Costs at End of Period	54.4	41.6	54.4	41.6
Colonial Life
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year			1,435.4	1,337.9
Deferred Policy Acquisition Cost			234.7	226.1
Deferred Policy Acquisition Costs, Amortization Expense			(163.9)	(153.4)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment and Other			0	0
Deferred Acquisition Costs at End of Period	$ 1,506.2	$ 1,410.6	$ 1,506.2	$ 1,410.6

Premium Income by Major Line of

Premium Income by Major Line of Business within Each Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information
Premium Income	$ 2,628.8	$ 2,525.9	$ 7,866.3	$ 7,494.3
Operating Segments
Segment Reporting Information
Premium Income	2,628.8	2,525.9	7,866.3	7,494.3
Operating Segments | Unum US
Segment Reporting Information
Premium Income	1,723.5	1,657.7	5,161.8	4,908.7
Operating Segments | Unum US | Group Long-term Disability
Segment Reporting Information
Premium Income	522.1	518.5	1,560.3	1,539.3
Operating Segments | Unum US | Group Short-term Disability
Segment Reporting Information
Premium Income	271.3	256.5	810.7	753
Operating Segments | Unum US | Group Life
Segment Reporting Information
Premium Income	447.8	423	1,337.9	1,254.3
Operating Segments | Unum US | Accidental Death & Dismemberment
Segment Reporting Information
Premium Income	47.1	44.1	139.3	131.2
Operating Segments | Unum US | Voluntary Benefits
Segment Reporting Information
Premium Income	219.3	209.5	665.1	637.4
Operating Segments | Unum US | Individual Disability
Segment Reporting Information
Premium Income	140.4	136.7	424.6	386.7
Operating Segments | Unum US | Dental and Vision
Segment Reporting Information
Premium Income	75.5	69.4	223.9	206.8
Operating Segments | Unum International
Segment Reporting Information
Premium Income	246.6	210.6	707.1	607.1
Operating Segments | Unum International | Group Long-term Disability
Segment Reporting Information
Premium Income	106.6	101.1	312.4	297.5
Operating Segments | Unum International | Group Life
Segment Reporting Information
Premium Income	58.8	44.2	156.3	124.5
Operating Segments | Unum International | Supplemental
Segment Reporting Information
Premium Income	41.4	34.6	125.1	99.9
Operating Segments | Unum International | Unum Poland
Segment Reporting Information
Premium Income	39.8	30.7	113.3	85.2
Operating Segments | Colonial Life
Segment Reporting Information
Premium Income	441.9	431.2	1,335	1,291.3
Operating Segments | Colonial Life | Accident, Sickness, and Disability
Segment Reporting Information
Premium Income	240.6	236.7	725.5	708
Operating Segments | Colonial Life | Life
Segment Reporting Information
Premium Income	113.1	106.2	342.6	318.1
Operating Segments | Colonial Life | Cancer and Critical Illness Colonial
Segment Reporting Information
Premium Income	88.2	88.3	266.9	265.2
Operating Segments | Closed Block
Segment Reporting Information
Premium Income	216.8	226.4	662.4	687.2
Operating Segments | Closed Block | Long-term Care
Segment Reporting Information
Premium Income	173.7	172.1	521.5	521.2
Operating Segments | Closed Block | Other Insurance Product Line
Segment Reporting Information
Premium Income	$ 43.1	$ 54.3	$ 140.9	$ 166

Selected Operating Statement Da

Selected Operating Statement Data by Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information
Premium Income	$ 2,628.8	$ 2,525.9	$ 7,866.3	$ 7,494.3
Net Investment Income	527.8	526	1,586.4	1,565.9
Other Income	73.3	71.6	222.5	210.6
Adjusted Operating Revenue	3,229.9	3,123.5	9,675.2	9,270.8
Adjusted Operating Income (Loss)	501.8	490.2	1,539.5	1,478.1
Operating Segments
Segment Reporting Information
Premium Income	2,628.8	2,525.9	7,866.3	7,494.3
Net Investment Income	527.8	526	1,586.4	1,565.9
Other Income	73.3	71.6	222.5	210.6
Adjusted Operating Revenue	3,229.9	3,123.5	9,675.2	9,270.8
Adjusted Operating Income (Loss)	501.8	490.2	1,539.5	1,478.1
Operating Segments | Unum US
Segment Reporting Information
Premium Income	1,723.5	1,657.7	5,161.8	4,908.7
Net Investment Income	161	166.2	476.1	481.5
Other Income	60.1	58	178.9	166.1
Adjusted Operating Revenue	1,944.6	1,881.9	5,816.8	5,556.3
Adjusted Operating Income (Loss)	363.3	357.8	1,106	1,013.4
Operating Segments | Unum International
Segment Reporting Information
Premium Income	246.6	210.6	707.1	607.1
Net Investment Income	30.4	27.3	94.5	104
Other Income	0.4	0.5	1.2	1
Adjusted Operating Revenue	277.4	238.4	802.8	712.1
Adjusted Operating Income (Loss)	40.3	36.8	120.2	118.7
Operating Segments | Colonial Life
Segment Reporting Information
Premium Income	441.9	431.2	1,335	1,291.3
Net Investment Income	39.6	39.3	119.4	114.6
Other Income	0.4	0.3	3.6	0.9
Adjusted Operating Revenue	481.9	470.8	1,458	1,406.8
Adjusted Operating Income (Loss)	113.4	102.9	344	312.3
Operating Segments | Closed Block
Segment Reporting Information
Premium Income	216.8	226.4	662.4	687.2
Net Investment Income	284.3	274.9	851.6	796
Other Income	12.4	12.8	37.7	40.1
Adjusted Operating Revenue	513.5	514.1	1,551.7	1,523.3
Adjusted Operating Income (Loss)	34.2	34.2	110.1	143.6
Operating Segments | Corporate
Segment Reporting Information
Premium Income	0	0	0	0
Net Investment Income	12.5	18.3	44.8	69.8
Other Income	0	0	1.1	2.5
Adjusted Operating Revenue	12.5	18.3	45.9	72.3
Adjusted Operating Income (Loss)	$ (49.4)	$ (41.5)	$ (140.8)	$ (109.9)

Assets by Segment (Detail)

Assets by Segment (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Segment Reporting Information
Total Assets	$ 64,140.5	$ 63,255.2
Operating Segments | Unum US
Segment Reporting Information
Total Assets	15,365.4	15,561.1
Operating Segments | Unum International
Segment Reporting Information
Total Assets	3,569.4	3,372.9
Operating Segments | Colonial Life
Segment Reporting Information
Total Assets	4,994.2	4,830.4
Operating Segments | Closed Block
Segment Reporting Information
Total Assets	35,527.4	35,272.8
Operating Segments | Corporate
Segment Reporting Information
Total Assets	$ 4,684.1	$ 4,218

Reconciliation of Total Revenue

Reconciliation of Total Revenue and Income Before Income Tax to Operating Revenue and Operating Income (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated
Total Revenue	$ 3,217	$ 3,092.5	$ 9,650.7	$ 9,240.8
Net Investment Loss	(12.9)	(31)	(24.5)	(30)
Adjusted Operating Revenue	3,229.9	3,123.5	9,675.2	9,270.8
Income Before Income Tax	814.6	261.7	1,805.8	1,211.4
Reserve Assumption Updates	357.4	(177.2)	357.4	(177.2)
Litigation Settlement, Loss	(15.3)	0	(15.3)	0
Adjusted Operating Income	501.8	490.2	1,539.5	1,478.1
Closed Block Individual Disability Reinsurance Transaction
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated
Amortization of the Cost of Reinsurance	(10.4)	(11.1)	(31.1)	(33.1)
Non-Contemporaneous Reinsurance	$ (6)	$ (9.2)	$ (20.2)	$ (26.4)

Segment Information Segments -

Segment Information Segments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2024 Integer
Segment Reporting [Abstract]
Number of Operating Segments	3

Employee Benefit Plans Net Peri

Employee Benefit Plans Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	$ 2.3	$ 2.3	$ 6.9	$ 6.9
Interest Cost	20.7	22	62.1	66
Expected Return on Plan Assets	(22.8)	(23)	(68.4)	(69.1)
Amortization of Net Actuarial (Gain) Loss	3.7	3.8	11	11.4
Amortization of Prior Service Credit	0	0	0	0
Net Periodic Benefit Cost (Credit)	3.9	5.1	11.6	15.2
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0	0	0	0
Interest Cost	1.9	1.9	5.7	5.7
Expected Return on Plan Assets	(2.1)	(2.1)	(6.3)	(6.3)
Amortization of Net Actuarial (Gain) Loss	0.7	0.6	2.2	1.9
Amortization of Prior Service Credit	0	0	0	0
Net Periodic Benefit Cost (Credit)	0.5	0.4	1.6	1.3
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0	0	0	0
Interest Cost	1	1.1	3	3.4
Expected Return on Plan Assets	(0.1)	(0.2)	(0.3)	(0.4)
Amortization of Net Actuarial (Gain) Loss	(0.2)	(2.6)	(0.8)	(7.9)
Amortization of Prior Service Credit	(0.1)	0	(0.2)	(0.1)
Net Periodic Benefit Cost (Credit)	$ 0.6	$ (1.7)	$ 1.7	$ (5)

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024		Sep. 30, 2023	Sep. 30, 2024		Sep. 30, 2023
Numerator
Net Income	$ 645.7		$ 202	$ 1,430.4		$ 953.2
Denominator
Weighted Average Common Shares - Basic	186,400,700		196,083,200	189,665,100		197,289,500
Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards	481,700		1,048,600	544,600		1,005,600
Weighted Average Common Shares - Assuming Dilution	186,882,400		197,131,800	190,209,700		198,295,100
Net Income Per Common Share
Basic	$ 3.46		$ 1.03	$ 7.54		$ 4.83
Assuming Dilution	$ 3.46		$ 1.02	$ 7.52		$ 4.81
Cost of Shares Repurchased	$ 202	[1]	$ 74.8	$ 504.8	[1]	$ 175.4
[1] 1

Treasury Stock Transactions (De

Treasury Stock Transactions (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Oct. 02, 2024	Jul. 02, 2024	Apr. 02, 2024	Jan. 03, 2024	Jul. 05, 2023
Equity, Class of Treasury Stock
Number of Treasury Shares Repurchased	3.7	1.5	9.7	3.9
Commissions Paid on Stock Repurchases				$ 0.1
Share Repurchases Excise Tax	2	$ 0.7	4.8	$ 1.2
October 2024 Accelerated Share Repurchase | Subsequent Event
Equity, Class of Treasury Stock
ASR prepayment amount					$ 150
July 2024 Accelerated Share Repurchase
Equity, Class of Treasury Stock
ASR prepayment amount						$ 150
April 2024 Accelerated Share Repurchase
Equity, Class of Treasury Stock
ASR prepayment amount							$ 125
January 2024 Accelerated Share Repurchase
Equity, Class of Treasury Stock
ASR prepayment amount								$ 100
July 2023 Accelerated Share Repurhcase
Equity, Class of Treasury Stock
ASR prepayment amount									$ 50
Repurchase Program Authorized in December 2022
Equity, Class of Treasury Stock
Authorized Amount of Treasury Share Repurchases Under Stock Repurchase Program	250		250
Remaining Amount of Treasury Share Repurchases Authorized Under Stock Repurchase Program	0		$ 0
Expiration Date of Share Repurchase Program Authorized in October 2021			Dec. 31, 2023
Repurchase Program Authorized in October 2023
Equity, Class of Treasury Stock
Authorized Amount of Treasury Share Repurchases Under Stock Repurchase Program	500		$ 500
Remaining Amount of Treasury Share Repurchases Authorized Under Stock Repurchase Program	0		$ 0
Expiration Date of Share Repurchase Program Authorized in October 2021			Jul. 31, 2024
Repurchase Program Authorized in July 2024
Equity, Class of Treasury Stock
Authorized Amount of Treasury Share Repurchases Under Stock Repurchase Program	1,000		$ 1,000
Remaining Amount of Treasury Share Repurchases Authorized Under Stock Repurchase Program	$ 964.2		$ 964.2

Stockholders' Equity and Earn_3

Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024		Sep. 30, 2023	Sep. 30, 2024		Sep. 30, 2023
Stockholders Equity and Earnings Per Common Share Additional Information [Abstract]
Outstanding Restricted Stock and Stock Success Unit Grant Prices Lower Limit	$ 18.78			$ 18.78
Outstanding Restricted Stock and Stock Success Unit Grant Prices Upper Limit	$ 52.40			$ 52.40
Antidilutive Securities Excluded from Computation of Earnings Per Share				200,000		400,000
Cost of Shares Repurchased	$ 202	[1]	$ 74.8	$ 504.8	[1]	$ 175.4
Number of Treasury Shares Repurchased	3,700,000		1,500,000	9,700,000		3,900,000
Authorized Shares of Preferred Stock	25,000,000			25,000,000
Par Value Per Share of Preferred Stock	$ 0.10			$ 0.10
Issued Shares of Preferred Stock	0			0
[1] 1

Loss on Legal Settlement (Detai

Loss on Legal Settlement (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Loss Contingencies
Litigation Settlement, Loss	$ 15.3	$ 0	$ 15.3	$ 0
Other Expense
Loss Contingencies
Litigation Settlement, Loss			10.4
Compensation Expense
Loss Contingencies
Litigation Settlement, Loss			$ 4.9

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Oct. 28, 2024
Five-Year $350 million Term Loan Facility
Debt Additional Information
Extinguishment of Debt, Amount	$ 350
6.000% Senior Notes due 2054
Debt Additional Information
Stated Interest Rate of Debt	6%
6.000% Senior Notes due 2054 | Senior Notes
Debt Additional Information
Debt Instrument, Face Amount	$ 400
4.046% Senior Notes due 2041 | Subsequent Event
Debt Additional Information
Debt Instrument, Face Amount		$ 400
Stated Interest Rate of Debt		4.046%

Allowance for Expected Credit L

Allowance for Expected Credit Losses on Premiums Receivable (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Credit Loss [Abstract]
Premium Receivable, Allowance for Credit Loss	$ 29.7	$ 27.1	$ 29.7	$ 26.8	$ 29.5	$ 28.7	$ 32.5
Premiums Receivable, Gross	626.6	630.4	626.6	$ 659.8	$ 612.4	$ 660.3	$ 557.6
Premium Receivable, Credit Loss Expense (Reversal)	$ 1	$ (2.4)	$ (2.8)