Investments (Tables)

9 Months Ended

Sep. 30, 2025

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Fair Values of Securities by Security Type

At September 30, 2025 and December 31, 2024, 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, 2025
	Amortized Cost, Gross of ACL1		ACL1		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	542.7	$	—	$	18.7	$	17.4	$	544.0
States, Municipalities, and Political Subdivisions	3,473.8		—		74.4		480.2		3,068.0
Foreign Governments	1,044.4		—		14.5		179.4		879.5
Public Utilities	4,990.2		—		180.8		282.2		4,888.8
Mortgage/Asset-Backed Securities2	1,128.9		—		10.0		17.3		1,121.6
All Other Corporate Bonds	23,673.7		15.2		558.6		1,536.6		22,680.5
Redeemable Preferred Stocks	8.0		—		—		0.2		7.8
Total Fixed Maturity Securities	$	34,861.7	$	15.2	$	857.0	$	2,513.3	$	33,190.2

	December 31, 2024
	Amortized Cost, Gross of ACL1		ACL1		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	544.6	$	—	$	13.9	$	28.0	$	530.5
States, Municipalities, and Political Subdivisions	3,795.6		—		65.5		569.7		3,291.4
Foreign Governments	912.1		—		9.5		153.5		768.1
Public Utilities	5,525.0		—		132.3		364.4		5,292.9
Mortgage/Asset-Backed Securities2	949.4		—		5.0		37.2		917.2
All Other Corporate Bonds	26,535.2		2.8		450.6		2,160.8		24,822.2
Redeemable Preferred Stocks	8.0		—		—		0.4		7.6
Total Fixed Maturity Securities	$	38,269.9	$	2.8	$	676.8	$	3,314.0	$	35,629.9

1Allowance for Credit Losses

2Includes credit-tranched securities collateralized by loan obligations, auto loans, and other asset types

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, 2025
	Less Than 12 Months				12 Months or Greater
	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	22.4	$	0.3	$	233.6	$	17.1
States, Municipalities, and Political Subdivisions	168.2		5.8		1,902.4		474.4
Foreign Governments	202.5		7.9		324.1		171.5
Public Utilities	618.8		20.0		1,540.9		262.2
Mortgage/Asset-Backed Securities1	56.8		0.4		281.7		16.9
All Other Corporate Bonds	1,776.7		47.9		11,260.3		1,488.7
Redeemable Preferred Stocks	—		—		3.7		0.2
Total Fixed Maturity Securities	$	2,845.4	$	82.3	$	15,546.7	$	2,431.0

	December 31, 2024
	Less Than 12 Months				12 Months or Greater
	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	43.7	$	4.1	$	201.3	$	23.9
States, Municipalities, and Political Subdivisions	425.8		15.3		1,926.2		554.4
Foreign Governments	171.9		10.6		266.3		142.9
Public Utilities	1,281.7		48.4		1,549.5		316.0
Mortgage/Asset-Backed Securities1	199.9		8.9		285.9		28.3
All Other Corporate Bonds	4,904.4		182.5		12,209.3		1,978.3
Redeemable Preferred Stocks	3.9		0.1		3.7		0.3
Total Fixed Maturity Securities	$	7,031.3	$	269.9	$	16,442.2	$	3,044.1

1Includes credit-tranched securities collateralized by loan obligations, auto loans, and other asset types

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, 2025
	Amortized Cost, Net of ACL1		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	1,432.4	$	3.9	$	459.6	$	6.4	$	970.3
Over 1 year through 5 years	6,736.2		157.1		3,523.8		99.4		3,270.1
Over 5 years through 10 years	7,357.1		257.5		3,651.7		369.7		3,593.2
Over 10 years	18,191.9		428.5		6,379.9		2,020.5		10,220.0
	33,717.6		847.0		14,015.0		2,496.0		18,053.6
Mortgage/Asset-Backed Securities2	1,128.9		10.0		783.1		17.3		338.5
Total Fixed Maturity Securities	$	34,846.5	$	857.0	$	14,798.1	$	2,513.3	$	18,392.1

	December 31, 2024
	Amortized Cost, Net of ACL1		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	1,484.1	$	4.1	$	432.4	$	6.2	$	1,049.6
Over 1 year through 5 years	7,688.2		123.5		2,840.8		196.6		4,774.3
Over 5 years through 10 years	8,404.6		236.4		3,486.1		565.5		4,589.4
Over 10 years	19,740.8		307.8		4,965.7		2,508.5		12,574.4
	37,317.7		671.8		11,725.0		3,276.8		22,987.7
Mortgage/Asset-Backed Securities2	949.4		5.0		431.4		37.2		485.8
Total Fixed Maturity Securities	$	38,267.1	$	676.8	$	12,156.4	$	3,314.0	$	23,473.5

1Allowance for Credit Losses

2Includes credit-tranched securities collateralized by loan obligations, auto loans, and other asset types

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, 2025:

					Gross Unrealized Loss
	Fair Value		Gross Unrealized Gain		Amount		Percent of Total Gross Unrealized Loss
	(in millions of dollars)
Investment-Grade	$	31,942.8	$	832.2	$	2,463.5	98.0	%
Below-Investment-Grade	1,247.4		24.8		49.8		2.0
Total Fixed Maturity Securities	$	33,190.2	$	857.0	$	2,513.3	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, 2025.

	Three Months Ended September 30
	2025		2024
	(in millions of dollars)
Balance, beginning of period	$	14.4	$	5.1
Change in allowance on securities with allowance recorded in previous period	1.6		0.2
Change in allowance on securities sold or otherwise disposed during the period	(0.8)		(2.4)
Balance, end of period	$	15.2	$	2.9

	Nine Months Ended September 30
	2025		2024
	(in millions of dollars)
Balance, beginning of period	$	2.8	$	2.2
Credit losses on securities for which credit losses were not previously recorded	10.5		2.9
Change in allowance on securities with allowance recorded in previous period	2.7		0.2
Change in allowance on securities sold or otherwise disposed during the period	(0.8)		(2.4)
Balance, end of period	$	15.2	$	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, 2025				December 31, 2024
	(in millions of dollars)
	Carrying Amount		Percent of Total		Carrying Amount		Percent of Total
Property Type
Apartment	$	657.1	30.9	%	$	658.2	29.6	%
Industrial	662.0		31.1		690.4		31.0
Office	319.9		15.0		338.4		15.2
Retail	462.9		21.7		496.2		22.3
Other	27.9		1.3		41.3		1.9
Total	$	2,129.8	100.0	%	$	2,224.5	100.0	%
Region
New England	$	50.6	2.4	%	$	52.6	2.4	%
Mid-Atlantic	161.7		7.6		167.2		7.5
East North Central	275.7		12.9		297.2		13.4
West North Central	145.6		6.8		151.1		6.8
South Atlantic	508.1		23.9		532.5		23.9
East South Central	86.5		4.1		95.1		4.3
West South Central	184.8		8.7		193.6		8.7
Mountain	271.5		12.7		278.7		12.5
Pacific	445.3		20.9		456.5		20.5
Total	$	2,129.8	100.0	%	$	2,224.5	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, 2025				December 31, 2024
	(in millions of dollars)
	Carrying Amount		Percent of Total		Carrying Amount		Percent of Total
Internal Mortgage Rating
AA	$	105.0	4.9	%	$	117.8	5.3	%
A	1,058.7		49.7		1,099.1		49.4
BBB	840.6		39.5		915.5		41.2
BB	110.5		5.2		85.0		3.8
B	15.0		0.7		7.1		0.3
Total	$	2,129.8	100.0	%	$	2,224.5	100.0	%
Loan-to-Value Ratio1
<= 65%	$	1,648.1	77.4	%	$	1,639.6	73.8	%
> 65% <= 75%	252.7		11.9		367.6		16.5
> 75% <= 85%	132.6		6.2		152.3		6.8
> 85%	96.4		4.5		65.0		2.9
Total	$	2,129.8	100.0	%	$	2,224.5	100.0	%

1Loan-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, 2025 and December 31, 2024, respectively:

	September 30, 2025
	Prior to 2021		2021		2022		2023		2024		2025		Total
	(in millions of dollars)
Internal Mortgage Rating
AA	$	98.9	$	6.1	$	—	$	—	$	—	$	—	$	105.0
A	806.5		165.6		23.8		9.5		6.4		49.0		1,060.8
BBB	520.2		142.8		62.2		56.8		39.5		23.3		844.8
BB	82.5		9.3		—		—		—		20.4		112.2
B	22.6		—		—		—		—		—		22.6
Total Amortized Cost	1,530.7		323.8		86.0		66.3		45.9		92.7		2,145.4
Allowance for credit losses	(13.4)		(0.9)		(0.3)		(0.4)		(0.2)		(0.4)		(15.6)
Carrying Amount	$	1,517.3	$	322.9	$	85.7	$	65.9	$	45.7	$	92.3	$	2,129.8
Loan-to-Value Ratio1
<=65%	$	1,267.1	$	240.6	$	39.7	$	38.5	$	11.6	$	54.7	$	1,652.2
>65<=75%	117.0		10.8		46.3		27.8		34.3		17.6		253.8
>75%<=85%	98.7		35.1		—		—		—		—		133.8
>85%	47.9		37.3		—		—		—		20.4		105.6
Total Amortized Cost	1,530.7		323.8		86.0		66.3		45.9		92.7		2,145.4
Allowance for credit losses	(13.4)		(0.9)		(0.3)		(0.4)		(0.2)		(0.4)		(15.6)
Carrying Amount	$	1,517.3	$	322.9	$	85.7	$	65.9	$	45.7	$	92.3	$	2,129.8

1Loan-to-Value Ratio utilizes the most recent internal valuation of the property

	December 31, 2024
	Prior to 2020		2020		2021		2022		2023		2024		Total
	(in millions of dollars)
Internal Mortgage Rating
AA	$	111.5	$	—	$	6.4	$	—	$	—	$	—	$	117.9
A	780.5		99.6		169.1		24.6		9.5		18.0		1,101.3
BBB	561.7		55.1		155.1		63.0		57.3		28.2		920.4
BB	86.8		—		—		—		—		—		86.8
B	14.2		—		—		—		—		—		14.2
Total Amortized Cost	1,554.7		154.7		330.6		87.6		66.8		46.2		2,240.6
Allowance for credit losses	(13.7)		(0.5)		(1.0)		(0.3)		(0.4)		(0.2)		(16.1)
Carrying Amount	$	1,541.0	$	154.2	$	329.6	$	87.3	$	66.4	$	46.0	$	2,224.5
Loan-to-Value Ratio1
<=65%	$	1,229.6	$	112.9	$	210.0	$	40.8	$	38.7	$	11.7	$	1,643.7
>65<=75%	154.1		33.7		72.1		46.8		28.1		34.5		369.3
>75%<=85%	126.4		8.1		20.1		—		—		—		154.6
>85%	44.6		—		28.4		—		—		—		73.0
Total Amortized Cost	1,554.7		154.7		330.6		87.6		66.8		46.2		2,240.6
Allowance for credit losses	(13.7)		(0.5)		(1.0)		(0.3)		(0.4)		(0.2)		(16.1)
Carrying Amount	$	1,541.0	$	154.2	$	329.6	$	87.3	$	66.4	$	46.0	$	2,224.5

1Loan-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, 2025 and 2024:

	Three Months Ended September 30, 2025
	Beginning of Period		Current Period Provisions		Write-Offs		Recoveries		End of Period
	(in millions of dollars)
Loan-to-Value Ratio1
<=65%	$	3.8	$	0.3	$	—	$	—	$	4.1
>65<=75%	1.5		(0.4)		—		—		1.1
>75%<=85%	1.1		0.9		(0.8)		—		1.2
>85%	9.2		—		—		—		9.2
Total	$	15.6	$	0.8	$	(0.8)	$	—	$	15.6

	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 Ratio1
<=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

	Nine Months Ended September 30, 2025
	Beginning of Year		Current Period Provisions		Write-Offs		Recoveries		End of Period
	(in millions of dollars)
Loan-to-Value Ratio1
<=65%	$	4.2	$	(0.1)	$	—	$	—	$	4.1
>65<=75%	1.7		(0.6)		—		—		1.1
>75%<=85%	2.2		(0.2)		(0.8)		—		1.2
>85%	8.0		1.2		—		—		9.2
Total	$	16.1	$	0.3	$	(0.8)	$	—	$	15.6

	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 Ratio1
<=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

1Loan-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, 2025		December 31, 2024
	Overnight and Continuous
	(in millions of dollars)
Borrowings
Public Utilities	$	3.9	$	5.2
Short Term Investments	—		1.0
All Other Corporate Bonds	105.1		56.5
Total Borrowings	109.0		62.7
Gross Amount of Recognized Liability for Securities Lending Transactions	109.0		62.7
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, 2025		December 31, 2024
	(in millions of dollars)
Carrying Value of FHLB Common Stock	$	38.0	$	26.7
Advances from FHLB	585.4		324.2
Carrying Value of Collateral Posted to FHLB
Fixed Maturity Securities	$	754.9	$	553.6
Commercial Mortgage Loans	1,124.7		908.2
Total Carrying Value of Collateral Posted to FHLB	$	1,879.6	$	1,461.8

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, 2025
	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	$	56.6	$	—	$	56.6	$	(56.6)	$	—	$	—
Securities Lending	129.8		—		129.8		(20.8)		(109.0)		—
Total	$	186.4	$	—	$	186.4	$	(77.4)	$	(109.0)	$	—
Financial Liabilities:
Derivatives	$	259.6	$	—	$	259.6	$	(258.5)	$	—	$	1.1
Securities Lending	109.0		—		109.0		(109.0)		—		—
Total	$	368.6	$	—	$	368.6	$	(367.5)	$	—	$	1.1

	December 31, 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	$	79.4	$	—	$	79.4	$	(75.7)	$	(3.2)	$	0.5
Securities Lending	94.0		—		94.0		(31.3)		(62.7)		—
Total	$	173.4	$	—	$	173.4	$	(107.0)	$	(65.9)	$	0.5
Financial Liabilities:
Derivatives	$	255.7	$	—	$	255.7	$	(254.3)	$	—	$	1.4
Securities Lending	62.7		—		62.7		(62.7)		—		—
Total	$	318.4	$	—	$	318.4	$	(317.0)	$	—	$	1.4

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
	2025		2024		2025		2024
	(in millions of dollars)
Fixed Maturity Securities	$	419.1	$	465.4	$	1,360.2	$	1,388.5
Derivatives	3.7		8.1		5.6		25.0
Mortgage Loans	22.0		22.0		65.7		66.6
Policy Loans	5.3		5.7		16.2		16.3
Other Long-term Investments
Perpetual Preferred Securities	(0.1)		—		0.7		0.3
Private Equity Partnerships1	21.7		19.6		65.3		72.6
Other	4.2		3.4		23.4		8.5
Short-term Investments	25.5		24.0		86.6		65.7
Gross Investment Income	501.4		548.2		1,623.7		1,643.5
Less Investment Expenses	21.8		17.5		64.5		48.3
Less Investment Income on Participation Fund Account Assets	2.8		2.9		8.5		8.8
Net Investment Income	$	476.8	$	527.8	$	1,550.7	$	1,586.4

1The net unrealized gain recognized in net investment income for the three and nine months ended September 30, 2025 related to private equity partnerships still held at September 30, 2025 was $28.8 million and $86.4 million, respectively, reduced by net management fees and partnership expenses of $(7.1) million and $(21.1) million, respectively. 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. 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
	2025		2024		2025		2024
	(in millions of dollars)
Fixed Maturity Securities
Gross Gains on Sales1	$	139.2	$	1.1	$	141.0	$	1.1
Gross Losses on Sales1	(11.5)		(8.5)		(71.5)		(29.7)
Impairment Loss1	—		(1.3)		(160.9)		(2.5)
Change in Allowance for Credit Losses	(0.8)		(0.2)		(12.4)		(3.1)
Mortgage Loans and Other Invested Assets
Gross Gains on Sales	0.2		0.4		7.6		0.4
Gross Losses on Sales	—		—		(0.4)		—
Impairment Loss	(1.6)		—		(5.4)		—
Change in Allowance for Credit Losses	—		(4.5)		0.5		(6.4)
Embedded Derivative in Modified Coinsurance Arrangement	3.3		(0.8)		2.4		6.1
All Other Derivatives	0.1		(2.2)		(3.1)		(0.2)
Foreign Currency Transactions	(0.9)		3.1		5.7		0.5
Other	—		—		—		9.3
Net Investment Gains (Losses)	$	128.0	$	(12.9)	$	(96.5)	$	(24.5)

1Our investment gains and losses on fixed maturity securities for the third quarter and first nine months of 2025 were driven primarily by the Closed Block long-term care and Unum US individual disability reinsurance transaction (Fortitude Re reinsurance transaction) which resulted in a net gain of $137.6 million in the third quarter of 2025 and a net loss of $46.8 million in the first nine months of 2025. In addition, we realized a $19.1 million loss on sales of fixed maturity securities relating to funding of a dividend from one of our subsidiaries in the first nine months of 2025.