Investments (Tables)

9 Months Ended

Sep. 30, 2024

Debt Securities, Available-for-sale [Line Items]

Investments Classified by Contractual Maturity Date

The amortized cost and estimated fair values of the Company’s Investments in Fixed Maturities at September 30, 2024 by contractual maturity were:

(Dollars in Millions)	Amortized Cost		Fair Value
Due in One Year or Less	$	264.2	$	261.2
Due after One Year to Five Years	874.3		856.2
Due after Five Years to Ten Years	1,031.0		929.6
Due after Ten Years	3,561.0		3,200.6
Mortgage- and Asset-backed Securities Not Due at a Single Maturity Date	1,728.9		1,624.4
Investments in Fixed Maturities	$	7,459.4	$	6,872.0

Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value

An aging of unrealized losses on the Company’s Investments in Fixed Maturities at September 30, 2024 is presented below.

	Less Than 12 Months				12 Months or Longer				Total
(Dollars in Millions)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Fixed Maturities:
U.S. Government and Government Agencies and Authorities	$	0.2	$	—	$	413.3	$	(78.3)	$	413.5	$	(78.3)
States and Political Subdivisions	43.1		(0.6)		996.5		(173.2)		1,039.6		(173.8)
Foreign Governments	—		—		1.7		(0.4)		1.7		(0.4)
Corporate Securities:
Bonds and Notes	98.2		(2.2)		2,785.8		(338.9)		2,884.0		(341.1)
Redeemable Preferred Stocks	1.2		—		6.7		(0.8)		7.9		(0.8)
Collateralized Loan Obligations	56.0		(0.3)		100.9		(8.0)		156.9		(8.3)
Other Mortgage- and Asset-backed	21.2		(0.1)		273.2		(29.9)		294.4		(30.0)
Total Fixed Maturities	$	219.9	$	(3.2)	$	4,578.1	$	(629.5)	$	4,798.0	$	(632.7)

    

An aging of unrealized losses on the Company’s Investments in Fixed Maturities at December 31, 2023 is presented below.

	Less Than 12 Months				12 Months or Longer				Total
(Dollars in Millions)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Fixed Maturities:
U.S. Government and Government Agencies and Authorities	$	52.0	$	(0.8)	$	401.6	$	(83.7)	$	453.6	$	(84.5)
States and Political Subdivisions	112.9		(2.3)		928.3		(187.5)		1,041.2		(189.8)
Foreign Governments	—		—		1.9		(0.6)		1.9		(0.6)
Corporate Securities:
Bonds and Notes	198.4		(5.5)		2,813.0		(378.3)		3,011.4		(383.8)
Redeemable Preferred Stocks	—		—		7.9		(0.8)		7.9		(0.8)
Collateralized Loan Obligations	38.8		(0.4)		747.7		(24.1)		786.5		(24.5)
Other Mortgage- and Asset-backed	15.7		(0.1)		287.3		(46.2)		303.0		(46.3)
Total Fixed Maturities	$	417.8	$	(9.1)	$	5,187.7	$	(721.2)	$	5,605.5	$	(730.3)

Debt Securities, Available-for-Sale, Allowance for Credit Loss

The Company monitors accrued interest and writes off amounts when they are not expected to be received.

	States and Political Subdivisions		Corporate Bonds and Notes		Total
(Dollars in Millions)
Balance, Beginning of Year	$	0.5	$	7.7	$	8.2
Additions for Securities for which No Previous Expected Credit Losses were    Recognized	—		2.0		2.0
Reductions Due to Sales	—		(0.8)		(0.8)
Net (Decrease) Increase in Allowance on Securities for which Expected Credit Losses were Previously Recognized	(0.3)		0.4		0.1
Balance, End of Period	$	0.2	$	9.3	$	9.5

The following table sets forth the change in allowance for credit losses on fixed maturities available-for-sale by major security type for the nine months ended September 30, 2023.

	States and Political Subdivisions		Corporate Bonds and Notes		Total
(Dollars in Millions)
Balance, Beginning of Year	$	0.7	$	8.9	$	9.6
Additions for Securities for which No Previous Expected Credit Losses were    Recognized	—		2.2		2.2
Reductions Due to Sales	(0.3)		(1.9)		(2.2)
Net Increase (Decrease) in Allowance on Securities for which Expected Credit Losses were Previously Recognized	0.1		(1.1)		(1.0)
Write-offs Charged Against Allowance	—		—		—
Balance, End of Period	$	0.5	$	8.1	$	8.6

Schedule of Other Investments

The carrying values of the Company’s Other Investments at September 30, 2024 and December 31, 2023 were:

(Dollars in Millions)	Sep 30, 2024		Dec 31, 2023
Equity Securities at Modified Cost	$	22.1	$	32.6
Real Estate at Depreciated Cost	103.1		94.7
Mortgage Loans	80.9		99.8
Other	0.4		14.8
Total Other Investments	$	206.5	$	241.9

Investment Income

Net Investment Income for the three and nine months ended September 30, 2024 and 2023 was:

	Three Months Ended				Nine Months Ended
(Dollars in Millions)	Sep 30, 2024		Sep 30, 2023		Sep 30, 2024		Sep 30, 2023
Investment Income:
Interest on Fixed Income Securities1,2	$	79.0	$	81.2	$	239.0	$	242.3
Dividends on Equity Securities Excluding Alternative Investments	0.9		1.2		4.6		3.4
Alternative Investments:
Equity Method Limited Liability Investments	0.9		4.3		(15.9)		8.2
Limited Liability Investments Included in Equity Securities	9.1		5.4		18.7		14.3
Total Alternative Investments	10.0		9.7		2.8		22.5
Short-term Investments	8.4		6.0		23.0		11.9
Loans to Policyholders	5.5		5.1		15.8		15.6
Real Estate	2.2		2.3		6.7		6.6
Company-Owned Life Insurance	9.7		6.4		25.7		22.6
Other	2.2		1.8		7.3		10.1
Total Investment Income	117.9		113.7		324.9		335.0
Investment Expenses:
Real Estate	1.8		1.7		6.1		6.0
Other Investment Expenses1,2	5.0		5.0		14.3		13.9
Total Investment Expenses	6.8		6.7		20.4		19.9
Net Investment Income	$	111.1	$	107.0	$	304.5	$	315.1
1In the first quarter of 2024, the Company changed its presentation of the details of investment performance to report interest expense incurred on Federal Home Loan Bank ("FHLB") borrowings as an offset to interest on fixed income securities since FHLB borrowings are used for spread lending purposes. The interest expense incurred on FHLB borrowings was previously reported within Other Investment Expenses. The prior period amounts presented above have been updated to reflect this change in presentation.
2Reduced by interest expense incurred on FHLB borrowings used for spread lending purposes of $4.8 million and $5.3 million for the three months ended September 30, 2024 and 2023, respectively, and $15.4 million and $17.5 million for the nine months ended September 30, 2024 and 2023, respectively.

Schedule of Realized Gain (Loss)

Gross gains and losses on sales of investments in fixed maturities and gains and losses associated with Ultra-Long Treasury Futures for the three and nine months ended September 30, 2024 and 2023 were:

	Three Months Ended				Nine Months Ended
(Dollars in Millions)	Sep 30, 2024		Sep 30, 2023		Sep 30, 2024		Sep 30, 2023
Fixed Maturities:
Gains on Sales	$	0.9	$	0.8	$	15.9	$	2.3
Losses on Sales	—		(1.2)		(2.6)		(10.5)
(Losses) Gains on Hedging Activity	—		(29.4)		(7.9)		(29.7)

Investments in Fixed Maturities

Debt Securities, Available-for-sale [Line Items]

Schedule of Available-for-sale Securities Reconciliation

The amortized cost and fair values of the Company’s Investments in Fixed Maturities at September 30, 2024 were:

	Amortized Cost		Gross Unrealized				Allowance for Expected Credit Losses		Fair Value
(Dollars in Millions)			Gains		Losses
U.S. Government and Government Agencies and Authorities	$	597.1	$	3.1	$	(78.3)	$	—	$	521.9
States and Political Subdivisions	1,530.4		17.3		(173.8)		(0.2)		1,373.7
Foreign Governments	5.4		0.1		(0.4)		—		5.1
Corporate Securities:
Bonds and Notes	4,071.0		31.6		(341.1)		(8.2)		3,753.3
Redeemable Preferred Stocks	11.0		0.1		(0.8)		—		10.3
Collateralized Loan Obligations	804.1		1.8		(8.3)		(1.1)		796.5
Other Mortgage- and Asset-backed	440.4		0.8		(30.0)		—		411.2
Investments in Fixed Maturities	$	7,459.4	$	54.8	$	(632.7)	$	(9.5)	$	6,872.0

The amortized cost and fair values of the Company’s Investments in Fixed Maturities at December 31, 2023 were:

	Amortized Cost		Gross Unrealized				Allowance for Expected Credit Losses		Fair Value
(Dollars in Millions)			Gains		Losses
U.S. Government and Government Agencies and Authorities	$	594.1	$	1.9	$	(84.5)	$	—	$	511.5
States and Political Subdivisions	1,575.9		16.3		(189.8)		(0.5)		1,401.9
Foreign Governments	4.4		—		(0.6)		—		3.8
Corporate Securities:
Bonds and Notes	4,046.8		35.5		(383.8)		(7.7)		3,690.8
Redeemable Preferred Stocks	9.0		0.1		(0.8)		—		8.3
Collateralized Loan Obligations	973.6		0.7		(24.5)		—		949.8
Other Mortgage- and Asset-backed	362.0		0.1		(46.3)		—		315.8
Investments in Fixed Maturities	$	7,565.8	$	54.6	$	(730.3)	$	(8.2)	$	6,881.9