Investments (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Fair Values of Securities by Security Type

At December 31, 2021 and 2020, 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:

	December 31, 2021
	Amortized Cost		ACL1		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	460.1	$	—	$	120.1	$	0.1	$	580.1
States, Municipalities, and Political Subdivisions	4,150.2		—		584.2		6.9		4,727.5
Foreign Governments	952.0		—		215.3		20.7		1,146.6
Public Utilities	5,266.4		—		1,159.4		9.8		6,416.0
Mortgage/Asset-Backed Securities	587.9		—		50.4		—		638.3
All Other Corporate Bonds	25,966.1		—		3,919.9		62.6		29,823.4
Redeemable Preferred Stocks	4.0		—		0.1		—		4.1
Total Fixed Maturity Securities	$	37,386.7	$	—	$	6,049.4	$	100.1	$	43,336.0

	December 31, 2020
	Amortized Cost		ACL1		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	559.0	$	—	$	150.8	$	—	$	709.8
States, Municipalities, and Political Subdivisions	3,609.9		—		652.8		1.5		4,261.2
Foreign Governments	902.9		—		266.5		1.2		1,168.2
Public Utilities	5,486.4		—		1,481.9		6.0		6,962.3
Mortgage/Asset-Backed Securities	1,019.9		—		88.0		0.2		1,107.7
All Other Corporate Bonds	24,958.8		6.8		5,013.5		46.9		29,918.6
Redeemable Preferred Stocks	9.6		—		—		0.1		9.5
Total Fixed Maturity Securities	$	36,546.5	$	6.8	$	7,653.5	$	55.9	$	44,137.3

1Allowance for Credit Losses

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.

	December 31, 2021
	Amortized Cost, Net of ACL		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	767.3	$	17.6	$	756.0	$	0.1	$	28.9
Over 1 year through 5 years	6,613.2		540.2		7,050.5		6.0		96.9
Over 5 years through 10 years	10,614.3		1,453.3		10,905.0		26.0		1,136.6
Over 10 years	18,804.0		3,987.9		20,778.4		68.0		1,945.4
	36,798.8		5,999.0		39,489.9		100.1		3,207.8
Mortgage/Asset-Backed Securities	587.9		50.4		609.0		—		29.3
Total Fixed Maturity Securities	$	37,386.7	$	6,049.4	$	40,098.9	$	100.1	$	3,237.1

	December 31, 2020
	Amortized Cost, Net of ACL		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	881.8	$	19.5	$	836.4	$	2.9	$	62.0
Over 1 year through 5 years	6,162.6		589.9		6,545.7		22.9		183.9
Over 5 years through 10 years	10,886.9		1,914.8		12,659.4		10.7		131.6
Over 10 years	17,588.5		5,041.3		22,089.2		19.2		521.4
	35,519.8		7,565.5		42,130.7		55.7		898.9
Mortgage/Asset-Backed Securities	1,019.9		88.0		1,101.6		0.2		6.1
Total Fixed Maturity Securities	$	36,539.7	$	7,653.5	$	43,232.3	$	55.9	$	905.0

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 December 31, 2021:

					Gross Unrealized Loss
	Fair Value		Gross Unrealized Gain		Amount		Percent of Total Gross Unrealized Loss
	(in millions of dollars)
Investment-Grade	$	40,359.0	$	5,814.9	$	88.4	88.3	%
Below-Investment-Grade	2,977.0		234.5		11.7		11.7
Total Fixed Maturity Securities	$	43,336.0	$	6,049.4	$	100.1	100.0	%

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

The following table presents a rollforward of the allowance for credit losses on available-for-sale fixed maturity securities, all of which are classified as "all other corporate bonds" in the preceding tables, at December 31, 2021:

	Year Ended December 31
	2021		2020
	(in millions of dollars)
Balance, beginning of period	$	6.8	$	—
Credit losses on securities for which credit losses were not previously recorded	—		44.5
Change in allowance due to change in intent to hold securities to maturity	—		(37.7)
Change in allowance on securities with allowance recorded in previous period	0.5		—
Change in allowance on securities sold during the period	(7.3)		—
Balance, end of period	$	—	$	6.8

Low Income Housing Tax Credits

The Company invests in tax credit partnerships primarily for the receipt of income tax credits and tax benefits derived from passive losses on the investments. Amounts recognized in the consolidated statements of income are as follows:

	Year Ended December 31
	2021		2020		2019
	(in millions of dollars)
Income Tax Credits	$	21.6	$	33.2	$	37.8
Amortization, Net of Tax	(15.0)		(21.9)		(25.2)
Income Tax Benefit	$	6.6	$	11.3	$	12.6

Mortgage Loans by Property Type and Geographic Region

The carrying amount of mortgage loans by property type and geographic region are presented below.

	December 31
	2021				2020
	(in millions of dollars)
	Carrying		Percent of		Carrying		Percent of
	Amount		Total		Amount		Total
Property Type
Apartment	$	780.0	30.5	%	$	638.0	26.2	%
Industrial	734.4		28.7		654.0		26.9
Office	467.2		18.2		517.8		21.3
Retail	533.3		20.8		575.6		23.7
Other	45.5		1.8		46.7		1.9
Total	$	2,560.4	100.0	%	$	2,432.1	100.0	%

Region
New England	$	54.9	2.1	%	$	40.0	1.6	%
Mid-Atlantic	214.7		8.4		202.5		8.2
East North Central	298.4		11.7		330.4		13.6
West North Central	193.1		7.5		196.1		8.1
South Atlantic	582.1		22.7		512.0		21.1
East South Central	120.7		4.7		110.0		4.5
West South Central	243.2		9.6		257.4		10.6
Mountain	290.6		11.3		268.8		11.1
Pacific	562.7		22.0		514.9		21.2
Total	$	2,560.4	100.0	%	$	2,432.1	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 credit quality indicators:

	December 31
	2021				2020
	(in millions of dollars)
	Carrying Amount		Percent of Total		Carrying Amount		Percent of Total
Internal Rating
AA	$	27.3	1.1	%	$	3.5	0.1	%
A	709.6		27.7		510.0		21.0
BBB	1,802.6		70.4		1,863.0		76.6
BB	20.9		0.8		39.4		1.6
B	—		—		16.2		0.7
Total	$	2,560.4	100.0	%	$	2,432.1	100.0	%

Loan-to-Value Ratio
<= 65%	$	1,346.1	52.6	%	$	1,189.4	48.9	%
> 65% <= 75%	1,076.8		42.0		1,000.3		41.1
> 75% <= 85%	114.9		4.5		155.8		6.4
> 85%	22.6		0.9		86.6		3.6
Total	$	2,560.4	100.0	%	$	2,432.1	100.0	%

Mortgage Loans by Credit Quality Indicators

The following table presents the amortized cost of our mortgage loans by year of origination and credit quality indicators for the years ended December 31, 2021 and 2020:

	Year Ended December 31, 2021
	Prior to 2017		2017		2018		2019		2020		2021		Total
	(in millions of dollars)
Internal Rating
AA	$	3.3	$	—	$	24.0	$	—	$	—	$	—	$	27.3
A	414.6		68.0		71.1		28.9		17.6		110.6		710.8
BBB	561.2		227.3		283.3		331.9		163.1		242.6		1,809.4
BB	5.0		10.2		6.0		—		—		—		21.2
B	—		—		—		—		—		—		—
Total Amortized Cost	984.1		305.5		384.4		360.8		180.7		353.2		2,568.7
Allowance for credit losses	(2.6)		(1.4)		(1.4)		(1.4)		(0.7)		(0.8)		(8.3)
Carrying Amount	$	981.5	$	304.1	$	383.0	$	359.4	$	180.0	$	352.4	$	2,560.4
Loan-to-Value Ratio
<=65%	$	779.1	$	146.9	$	163.0	$	80.7	$	54.3	$	124.7	$	1,348.7
>65<=75%	115.7		115.4		215.4		280.1		126.4		228.5		1,081.5
>75%<=85%	89.3		26.3		—		—		—		—		115.6
>85%	—		16.9		6.0		—		—		—		22.9
Total Amortized Cost	984.1		305.5		384.4		360.8		180.7		353.2		2,568.7
Allowance for credit losses	(2.6)		(1.4)		(1.4)		(1.4)		(0.7)		(0.8)		(8.3)
Carrying Amount	$	981.5	$	304.1	$	383.0	$	359.4	$	180.0	$	352.4	$	2,560.4

	Year Ended December 31, 2020
	Prior to 2016		2016		2017		2018		2019		2020		Total
	(in millions of dollars)
Internal Rating
AA	$	3.5	$	—	$	—	$	—	$	—	$	—	$	3.5
A	240.3		119.5		56.3		60.2		16.9		18.0		511.2
BBB	482.6		287.8		253.9		331.8		351.9		166.4		1,874.4
BB	29.4		—		10.5		—		—		—		39.9
B	16.2		—		—		—		—		—		16.2
Total Amortized Cost	772.0		407.3		320.7		392.0		368.8		184.4		2,445.2
Allowance for credit losses	(2.4)		(2.0)		(1.9)		(2.4)		(2.9)		(1.5)		(13.1)
Carrying Amount	$	769.6	$	405.3	$	318.8	$	389.6	$	365.9	$	182.9	$	2,432.1
Loan-to-Value Ratio
<=65%	$	598.5	$	257.5	$	139.0	$	77.8	$	82.8	$	37.2	$	1,192.8
>65<=75%	47.2		122.5		109.9		294.8		286.0		147.2		1,007.6
>75%<=85%	78.7		27.3		37.9		13.3		—		—		157.2
>85%	47.6		—		33.9		6.1		—		—		87.6
Total Amortized Cost	772.0		407.3		320.7		392.0		368.8		184.4		2,445.2
Allowance for credit losses	(2.4)		(2.0)		(1.9)		(2.4)		(2.9)		(1.5)		(13.1)
Carrying Amount	$	769.6	$	405.3	$	318.8	$	389.6	$	365.9	$	182.9	$	2,432.1

Financing Receivable, Allowance for Credit Loss

The following tables present a roll forward of allowance for expected credit losses by loan-to-value ratio for the years ended December 31, 2021 and 2020:

	Year Ended December 31, 2021
	Beginning of Period		Current Period Provisions		Write-Offs		Recoveries		End of Period
	(in millions of dollars)
Loan-to-Value Ratio
<=65%	$	3.4	$	(0.8)	$	—	$	—	$	2.6
>65<=75%	7.3		(2.6)		—		—		4.7
>75%<=85%	1.3		(0.6)		—		—		0.7
>85%	1.1		(0.8)		—		—		0.3
Total	$	13.1	$	(4.8)	$	—	$	—	$	8.3

	Year Ended December 31, 2020
	Beginning of Period		Current Period Provisions		Write-Offs		Recoveries		End of Period
	(in millions of dollars)
Loan-to-Value Ratio
<=65%	$	2.8	$	0.6	$	—	$	—	$	3.4
>65<=75%	4.6		2.7		—		—		7.3
>75%<=85%	0.5		0.8		—		—		1.3
>85%	0.4		0.7		—		—		1.1
Total	$	8.3	$	4.8	$	—	$	—	$	13.1

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:

	December 31
	2021		2020
	Overnight and Continuous
	(in millions of dollars)
Borrowings
United States Government and Government Agencies and Authorities	$	0.1	$	0.1
State, Municipalities, and Political Subdivisions	0.1		0.4
Public Utilities	3.1		0.3
All Other Corporate Bonds	91.5		16.8
Total Borrowings	$	94.8	$	17.6
Gross Amount of Recognized Liability for Securities Lending Transactions	94.8		17.6
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:

	December 31
	2021		2020
	(in millions of dollars)
Carrying Value of FHLB Common Stock	$	22.1	$	28.2
Advances from FHLB	160.9		312.2
Carrying Value of Collateral Posted to FHLB
Fixed Maturity Securities	$	786.1	$	944.0
Commercial Mortgage Loans	930.0		1,072.5
Total Carrying Value of Collateral Posted to FHLB	$	1,716.1	$	2,016.5

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.

	December 31, 2021
	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	$	39.5	$	—	$	39.5	$	(9.8)	$	(28.4)	$	1.3
Securities Lending	283.7		—		283.7		(188.9)		(94.8)		—
Total	$	323.2	$	—	$	323.2	$	(198.7)	$	(123.2)	$	1.3
Financial Liabilities:
Derivatives	$	35.0	$	—	$	35.0	$	(34.0)	$	—	$	1.0
Securities Lending	94.8		—		94.8		(94.8)		—		—
Total	$	129.8	$	—	$	129.8	$	(128.8)	$	—	$	1.0

	December 31, 2020
	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	$	19.8	$	—	$	19.8	$	(10.1)	$	(8.7)	$	1.0
Securities Lending	96.6		—		96.6		(79.0)		(17.6)		—
Total	$	116.4	$	—	$	116.4	$	(89.1)	$	(26.3)	$	1.0
Financial Liabilities:
Derivatives	$	59.7	$	—	$	59.7	$	(59.0)	$	—	$	0.7
Securities Lending	17.6		—		17.6		(17.6)		—		—
Total	$	77.3	$	—	$	77.3	$	(76.6)	$	—	$	0.7

Net Investment Income

Net Investment Income

Net investment income reported in our consolidated statements of income is presented below. Certain prior period amounts have been reclassified to conform to the current period presentation.

	Year Ended December 31
	2021		2020		2019
	(in millions of dollars)
Fixed Maturity Securities	$	1,888.2	$	2,164.0	$	2,213.6
Derivatives	68.6		78.7		73.4
Mortgage Loans	105.0		108.9		103.3
Policy Loans	19.7		20.0		19.9
Other Long-term Investments
Perpetual Preferred Securities1	6.9		(2.1)		5.4
Private Equity Partnerships2	165.4		19.8		31.7
Other	5.5		3.9		3.9
Short-term Investments	1.3		10.5		29.0
Gross Investment Income	2,260.6		2,403.7		2,480.2
Less Investment Expenses	35.1		30.6		32.1
Less Investment Income on Participation Fund Account Assets	12.3		12.4		12.8
Net Investment Income	$	2,213.2	$	2,360.7	$	2,435.3

1 The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2021 related to perpetual preferred securities still held at December 31, 2021 was $4.4 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2020 and 2019 related to perpetual preferred securities still held at year-end was $(4.6) million and $3.3 million, respectively

2 The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2021 related to private equity partnerships still held at December 31, 2021 was $107.8 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2020 and 2019 related to private equity partnerships still held at year-end was $(8.7) million and $6.8 million, respectively. See Note 2 for further discussion of private equity partnerships.

Realized Investment Gains and Losses Reported in Consolidated Statements of Income

Investment Gain and Loss

Investment gains and losses are as follows:

	Year Ended December 31
	2021		2020		2019
	(in millions of dollars)
Fixed Maturity Securities
Gross Gains on Sales1	$	76.2	$	1,332.8	$	22.9
Gross Losses on Sales	(11.5)		(20.3)		(32.6)
Credit Losses	(9.3)		(53.6)		(25.3)
Mortgage Loans and Other Invested Assets
Gross Gains on Sales	5.8		1.9		4.6
Gross Losses on Sales	—		(0.3)		(0.3)
Impairment Loss	—		(36.6)		—
Change in Allowance for Credit Losses	4.7		(4.6)		—
Embedded Derivative in Modified Coinsurance Arrangement	9.7		(17.0)		8.3
All Other Derivatives	3.1		(2.5)		(0.1)
Foreign Currency Transactions	(2.0)		(0.7)		(0.7)
Net Investment Gain (Loss)	$	76.7	$	1,199.1	$	(23.2)

1Gross gains on sales of fixed maturity securities for the year ended December 31, 2021 includes gains of $67.6 million as a result of the second phase of the reinsurance transaction that we completed during the first quarter of 2021. Gross gains on sales of fixed maturity securities for the year ended December 31, 2020 includes gains of $1,302.3 million as a result of the first phase of the reinsurance transaction that we completed during the fourth quarter of 2020. See Note 12 for further discussion.

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.

	December 31, 2021
	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	$	9.3	$	0.1	$	—	$	—
States, Municipalities, and Political Subdivisions	326.4		6.9		0.4		—
Foreign Governments	234.4		18.9		10.7		1.8
Public Utilities	263.3		9.1		17.6		0.7
Mortgage/Asset-Backed Securities	29.2		—		0.1		—
All Other Corporate Bonds	2,146.3		51.6		199.4		11.0
Total Fixed Maturity Securities	$	3,008.9	$	86.6	$	228.2	$	13.5

	December 31, 2020
	Less Than 12 Months				12 Months or Greater
	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
	(in millions of dollars)
States, Municipalities, and Political Subdivisions	$	133.4	$	1.5	$	0.1	$	—
Foreign Governments	20.3		1.2		—		—
Public Utilities	76.3		3.7		25.4		2.3
Mortgage/Asset-Backed Securities	3.0		0.1		3.1		0.1
All Other Corporate Bonds	520.4		22.4		113.5		24.5
Redeemable Preferred Stocks	9.5		0.1		—		—
Total Fixed Maturity Securities	$	762.9	$	29.0	$	142.1	$	26.9