Investments (Tables)

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Fair Values of Securities by Security Type

At December 31, 2020 and 2019, 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, 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

	December 31, 2019
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	1,246.1	$	156.0	$	0.4	$	1,401.7
States, Municipalities, and Political Subdivisions	2,863.1		507.6		7.3		3,363.4
Foreign Governments	843.5		175.2		1.0		1,017.7
Public Utilities	6,436.7		1,303.7		8.2		7,732.2
Mortgage/Asset-Backed Securities	1,377.8		101.3		0.4		1,478.7
All Other Corporate Bonds	28,273.1		4,211.2		73.9		32,410.4
Redeemable Preferred Stocks	39.0		0.6		—		39.6
Total Fixed Maturity Securities	$	41,079.3	$	6,455.6	$	91.2	$	47,443.7

1Allowance for Credit Losses

Length of Time Fixed Maturity Securities had been in a Gross Unrealized Loss Position

The following charts indicate the length of time our fixed maturity securities have been in a gross unrealized loss position.

	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

	December 31, 2019
	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	$	110.2	$	0.4	$	—	$	—
States, Municipalities, and Political Subdivisions	331.0		7.3		0.3		—
Foreign Governments	69.4		1.0		—		—
Public Utilities	168.3		2.6		37.0		5.6
Mortgage/Asset-Backed Securities	47.0		0.4		3.1		—
All Other Corporate Bonds	579.1		29.1		379.8		44.8
Total Fixed Maturity Securities	$	1,305.0	$	40.8	$	420.2	$	50.4

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, 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

	December 31, 2019
	Total Amortized Cost		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	821.5	$	14.5	$	832.6	$	0.2	$	3.2
Over 1 year through 5 years	6,286.2		456.5		6,423.4		41.7		277.6
Over 5 years through 10 years	13,570.8		1,688.3		14,881.3		14.6		363.2
Over 10 years	19,023.0		4,195.0		22,152.6		34.3		1,031.1
	39,701.5		6,354.3		44,289.9		90.8		1,675.1
Mortgage/Asset-Backed Securities	1,377.8		101.3		1,428.6		0.4		50.1
Total Fixed Maturity Securities	$	41,079.3	$	6,455.6	$	45,718.5	$	91.2	$	1,725.2

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, 2020:

					Gross Unrealized Loss
	Fair Value		Gross Unrealized Gain		Amount		Percent of Total Gross Unrealized Loss
	(in millions of dollars)
Investment-Grade	$	40,637.2	$	7,371.5	$	18.1	32.4	%
Below-Investment-Grade	3,500.1		282.0		37.8		67.6
Total Fixed Maturity Securities	$	44,137.3	$	7,653.5	$	55.9	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, 2020:

	Year Ended
	(in millions of dollars)
Balance, beginning of period	$	—
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	—
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
	2020		2019		2018
	(in millions of dollars)
Income Tax Credits	$	33.2	$	37.8	$	41.4
Amortization, Net of Tax	(21.9)		(25.2)		(28.1)
Income Tax Benefit	$	11.3	$	12.6	$	13.3

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
	2020				2019
	(in millions of dollars)
	Carrying		Percent of		Carrying		Percent of
	Amount		Total		Amount		Total
Property Type
Apartment	$	638.0	26.2	%	$	608.8	25.4	%
Industrial	654.0		26.9		623.6		26.0
Office	517.8		21.3		549.3		22.9
Retail	575.6		23.7		567.5		23.7
Other	46.7		1.9		47.8		2.0
Total	$	2,432.1	100.0	%	$	2,397.0	100.0	%

Region
New England	$	40.0	1.6	%	$	28.9	1.2	%
Mid-Atlantic	202.5		8.2		184.5		7.7
East North Central	330.4		13.6		329.2		13.7
West North Central	196.1		8.1		215.4		9.0
South Atlantic	512.0		21.1		509.2		21.2
East South Central	110.0		4.5		114.3		4.8
West South Central	257.4		10.6		246.6		10.3
Mountain	268.8		11.1		268.2		11.2
Pacific	514.9		21.2		500.7		20.9
Total	$	2,432.1	100.0	%	$	2,397.0	100.0	%

Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value

Mortgage loans, sorted by the applicable credit quality indicators, are as follows:

	December 31
	2020				2019
	(in millions of dollars)
	Carrying Amount		Percent of Total		Carrying Amount		Percent of Total
Internal Rating
AA	$	3.5	0.1	%	$	—	—	%
A	510.0		21.0	%	485.6		20.3	%
BBB	1,863.0		76.6		1,911.4		79.7
BB	39.4		1.6		—		—
B	16.2		0.7		—		—
Total	$	2,432.1	100.0	%	$	2,397.0	100.0	%

Loan-to-Value Ratio
<= 65%	$	1,189.4	48.9	%	$	1,215.1	50.7	%
> 65% <= 75%	1,000.3		41.1		1,053.0		43.9
> 75% <= 85%	155.8		6.4		91.4		3.8
> 85%	86.6		3.6		37.5		1.6
Total	$	2,432.1	100.0	%	$	2,397.0	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 at 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 table presents a rollforward of allowance for expected credit losses by loan-to-value ratio:

	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
	2020		2019
	Overnight and Continuous
	(in millions of dollars)
Borrowings
United States Government and Government Agencies and Authorities	$	0.1	$	—
State, Municipalities, and Political Subdivisions	0.4		—
Public Utilities	0.3		—
All Other Corporate Bonds	16.8		—
Total Borrowings	$	17.6	$	—
Gross Amount of Recognized Liability for Securities Lending Transactions	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
	2020		2019
	(in millions of dollars)
Carrying Value of FHLB Common Stock	$	28.2	$	18.5
Advances from FHLB	312.2		—
Carrying Value of Collateral Posted to FHLB
Fixed Maturity Securities	$	944.0	$	182.1
Commercial Mortgage Loans	1,072.5		164.4
Total Carrying Value of Collateral Posted to FHLB	$	2,016.5	$	346.5

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, 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

	December 31, 2019
	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	$	27.5	$	—	$	27.5	$	(4.0)	$	(23.5)	$	—
Securities Lending	176.4		—		176.4		(176.4)		—		—
Total	$	203.9	$	—	$	203.9	$	(180.4)	$	(23.5)	$	—
Financial Liabilities:
Derivatives	$	34.6	$	—	$	34.6	$	(31.3)	$	—	$	3.3

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
	2020		2019		2018
	(in millions of dollars)
Fixed Maturity Securities	$	2,164.0	$	2,213.6	$	2,239.7
Derivatives	78.7		73.4		66.1
Mortgage Loans	108.9		103.3		110.1
Policy Loans	20.0		19.9		18.6
Other Long-term Investments
Perpetual Preferred Securities1	(2.1)		5.4		(0.2)
Private Equity Partnerships2	19.8		31.7		36.0
Other	3.9		3.9		8.4
Short-term Investments	10.5		29.0		23.7
Gross Investment Income	2,403.7		2,480.2		2,502.4
Less Investment Expenses	30.6		32.1		35.2
Less Investment Income on Participation Fund Account Assets	12.4		12.8		13.5
Net Investment Income	$	2,360.7	$	2,435.3	$	2,453.7

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

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

Realized Investment Gains and Losses Reported in Consolidated Statements of Income

Realized Investment Gain and Loss

Realized investment gains and losses are as follows:

	Year Ended December 31
	2020		2019		2018
	(in millions of dollars)
Fixed Maturity Securities
Gross Gains on Sales1	$	1,332.8	$	22.9	$	9.7
Gross Losses on Sales	(20.3)		(32.6)		(15.2)
Credit Losses	(53.6)		(25.3)		(17.5)
Mortgage Loans and Other Invested Assets
Gross Gains on Sales	1.9		4.6		0.5
Gross Losses on Sales	(0.3)		(0.3)		—
Impairment Loss	(36.6)		—		(1.4)
Credit Losses	(4.6)		—		—
Embedded Derivative in Modified Coinsurance Arrangement	(17.0)		8.3		(15.2)
All Other Derivatives	(2.5)		(0.1)		0.3
Foreign Currency Transactions	(0.7)		(0.7)		(0.7)
Net Realized Investment Gain (Loss)	$	1,199.1	$	(23.2)	$	(39.5)

1Gross gains on sales of fixed maturity securities includes gains of $1,302.3 million as a result of the reinsurance transaction that we entered into during the fourth quarter of 2020. See Note 12 for further discussion.