Fair Value (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Composition of Investment Portfolio by Major Security Type

The composition of the investment portfolio by major security type and our outstanding debt was:

	Fair Value
(millions)	Level 1		Level 2		Level 3		Total		Cost
March 31, 2021
Fixed maturities:
U.S. government obligations	$	16,073.4	$	0	$	0	$	16,073.4	$	16,002.7
State and local government obligations	0		2,624.1		0		2,624.1		2,574.8
Corporate debt securities	0		10,436.2		0		10,436.2		10,095.2
Subtotal	16,073.4		13,060.3		0		29,133.7		28,672.7
Asset-backed securities:
Residential mortgage-backed	0		553.2		0		553.2		548.3
Commercial mortgage-backed	0		5,892.0		0		5,892.0		5,868.3
Other asset-backed	0		3,323.4		0		3,323.4		3,293.5
Subtotal asset-backed securities	0		9,768.6		0		9,768.6		9,710.1
Redeemable preferred stocks:
Financials	0		50.6		0		50.6		51.0
Utilities	0		11.4		0		11.4		10.0
Industrials	10.6		116.9		0		127.5		120.2
Subtotal redeemable preferred stocks	10.6		178.9		0		189.5		181.2
Total fixed maturities	16,084.0		23,007.8		0		39,091.8		38,564.0
Short-term investments	2,227.8		15.3		0		2,243.1		2,243.1
Total available-for-sale securities	18,311.8		23,023.1		0		41,334.9		40,807.1
Equity securities:
Nonredeemable preferred stocks:
Financials	113.8		1,274.7		35.0		1,423.5		1,373.9
Utilities	0		41.9		0		41.9		39.9
Industrials	0		25.2		16.6		41.8		40.1
Subtotal nonredeemable preferred stocks	113.8		1,341.8		51.6		1,507.2		1,453.9
Common equities:
Common stocks	4,555.3		0		0		4,555.3		1,201.3
Other risk investments	0		0		3.2		3.2		3.2
Subtotal common equities	4,555.3		0		3.2		4,558.5		1,204.5
Total equity securities	4,669.1		1,341.8		54.8		6,065.7		2,658.4
Total portfolio	$	22,980.9	$	24,364.9	$	54.8	$	47,400.6	$	43,465.5
Debt	$	0	$	6,195.2	$	0	$	6,195.2	$	5,396.8

	Fair Value
(millions)	Level 1		Level 2		Level 3		Total		Cost
March 31, 2020
Fixed maturities:
U.S. government obligations	$	11,495.7	$	0	$	0	$	11,495.7	$	10,841.2
State and local government obligations	0		2,304.2		0		2,304.2		2,243.9
Corporate debt securities	0		9,491.9		0		9,491.9		9,452.9
Subtotal	11,495.7		11,796.1		0		23,291.8		22,538.0
Asset-backed securities:
Residential mortgage-backed	0		556.6		0		556.6		574.3
Commercial mortgage-backed	0		5,664.3		0		5,664.3		5,822.4
Other asset-backed	0		4,639.1		0		4,639.1		4,674.9
Subtotal asset-backed securities	0		10,860.0		0		10,860.0		11,071.6
Redeemable preferred stocks:
Financials	0		47.2		0		47.2		51.4
Utilities	0		9.2		0		9.2		10.0
Industrials	7.3		61.1		0		68.4		90.1
Subtotal redeemable preferred stocks	7.3		117.5		0		124.8		151.5
Total fixed maturities	11,503.0		22,773.6		0		34,276.6		33,761.1
Short-term investments	2,438.4		85.8		0		2,524.2		2,524.2
Total available-for-sale securities	13,941.4		22,859.4		0		36,800.8		36,285.3
Equity securities:
Nonredeemable preferred stocks:
Financials	105.5		752.3		13.1		870.9		937.4
Utilities	0		32.0		0		32.0		40.0
Industrials	0		15.3		15.2		30.5		40.1
Subtotal nonredeemable preferred stocks	105.5		799.6		28.3		933.4		1,017.5
Common equities:
Common stocks	2,607.8		0		0		2,607.8		1,112.9
Other risk investments	0		0		0.3		0.3		0.3
Subtotal common equities	2,607.8		0		0.3		2,608.1		1,113.2
Total equity securities	2,713.3		799.6		28.6		3,541.5		2,130.7
Total portfolio	$	16,654.7	$	23,659.0	$	28.6	$	40,342.3	$	38,416.0
Debt	$	0	$	6,108.6	$	0	$	6,108.6	$	5,394.0

	Fair Value
(millions)	Level 1		Level 2		Level 3		Total		Cost
December 31, 2020
Fixed maturities:
U.S. government obligations	$	12,740.0	$	0	$	0	$	12,740.0	$	12,437.9
State and local government obligations	0		3,221.8		0		3,221.8		3,099.4
Corporate debt securities	0		10,185.2		0		10,185.2		9,579.7
Subtotal	12,740.0		13,407.0		0		26,147.0		25,117.0
Asset-backed securities:
Residential mortgage-backed	0		509.5		0		509.5		503.3
Commercial mortgage-backed	0		6,175.1		0		6,175.1		6,042.6
Other asset-backed	0		3,784.6		0		3,784.6		3,745.0
Subtotal asset-backed securities	0		10,469.2		0		10,469.2		10,290.9
Redeemable preferred stocks:
Financials	0		51.6		0		51.6		51.1
Utilities	0		11.7		0		11.7		10.0
Industrials	10.8		120.6		0		131.4		120.1
Subtotal redeemable preferred stocks	10.8		183.9		0		194.7		181.2
Total fixed maturities	12,750.8		24,060.1		0		36,810.9		35,589.1
Short-term investments	4,704.9		513.6		0		5,218.5		5,218.5
Total available-for-sale securities	17,455.7		24,573.7		0		42,029.4		40,807.6
Equity securities:
Nonredeemable preferred stocks:
Financials	117.7		1,212.3		35.0		1,365.0		1,278.6
Utilities	0		41.9		0		41.9		40.0
Industrials	0		24.3		16.7		41.0		40.1
Subtotal nonredeemable preferred stocks	117.7		1,278.5		51.7		1,447.9		1,358.7
Common equities:
Common stocks	4,049.9		0		0		4,049.9		1,184.2
Other risk investments	0		0		3.1		3.1		3.1
Subtotal common equities	4,049.9		0		3.1		4,053.0		1,187.3
Total equity securities	4,167.6		1,278.5		54.8		5,500.9		2,546.0
Total portfolio	$	21,623.3	$	25,852.2	$	54.8	$	47,530.3	$	43,353.6
Debt	$	0	$	6,793.5	$	0	$	6,793.5	$	5,396.1

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation

The following tables provide a summary of changes in fair value associated with Level 3 assets for the three months ended March 31, 2021 and 2020:

	Level 3 Fair Value
(millions)	Fair Value at December 31, 2020		Calls/ Maturities/ Paydowns		Purchases		Sales		Net Realized (Gain)/Loss on Sales		Change in Valuation		Net Transfers In (Out)		Fair Value at March 31, 2021
Equity securities:
Nonredeemable preferred stocks:
Financials	$	35.0	$	0	$	0	$	0	$	0	$	0	$	0	$	35.0
Industrials	16.7		0		0		0		0		(0.1)		0		16.6
Common equities:
Other risk investments	3.1		0		0.1		0		0		0		0		3.2
Total Level 3 securities	$	54.8	$	0	$	0.1	$	0	$	0	$	(0.1)	$	0	$	54.8

	Level 3 Fair Value
(millions)	Fair Value at December 31, 2019		Calls/ Maturities/ Paydowns		Purchases		Sales		Net Realized (Gain)/Loss on Sales		Change in Valuation		Net Transfers In (Out)		Fair Value at March 31, 2020
Equity securities:
Nonredeemable preferred stocks:
Financials	$	27.1	$	0	$	0	$	0	$	0	$	(14.0)	$	0	$	13.1
Industrials	16.0		0		0		0		0		$	(0.8)	0		15.2
Common equities:
Other risk investments	0.3		0		0		0		0		0		0		0.3
Total Level 3 securities	$	43.4	$	0	$	0	$	0	$	0	$	(14.8)	$	0	$	28.6

Fair Value Measurement Inputs and Valuation Techniques

The following tables provide a summary of the quantitative information about Level 3 fair value measurements for our applicable securities at March 31, 2021 and 2020, and December 31, 2020:

	Quantitative Information about Level 3 Fair Value Measurements
($ in millions)	Fair Value at March 31, 2021		Valuation Technique	Unobservable Input	Unobservable Input Assumption
Equity securities:
Nonredeemable preferred stocks:
Financials1	$	25.0	Internal price	Unadjusted purchase price per share	3.7
Financials2	10.0		Internal price	Unadjusted purchase price per share	16.9
Industrials	6.9		Pricing firm	Market approach (guideline public company method)	5.4
Industrials	9.7		Pricing firm	Market approach (guideline public company method)	4.8
Subtotal Level 3 securities	51.6
Pricing exemption securities	3.2
Total Level 3 securities	$	54.8

1 This security was purchased in May 2020.

2 This security was purchased in November 2020.

	Quantitative Information about Level 3 Fair Value Measurements
($ in millions)	Fair Value at March 31, 2020		Valuation Technique	Unobservable Input	Unobservable Input Assumption
Equity securities:
Nonredeemable preferred stocks:
Financials	$	13.1	Internal price	Market approach (guideline public company method)	4.4
Industrials1	7.1		Internal price	Market approach (guideline public company method)	5.6
Industrials1	8.1		Internal price	Market approach (guideline public company method)	4.0
Subtotal Level 3 securities	28.3
Pricing exemption securities	0.3
Total Level 3 securities	$	28.6

1Modified prior year disclosure to present securities individually to conform to the current year presentation.

	Quantitative Information about Level 3 Fair Value Measurements
($ in millions)	Fair Value at December 31, 2020		Valuation Technique	Unobservable Input	Unobservable Input Assumption
Equity securities:
Nonredeemable preferred stocks:
Financials1	$	25.0	Internal price	Unadjusted purchase price per share	3.7
Financials2	10.0		Internal price	Unadjusted purchase price per share	16.9
Industrials	6.9		Pricing firm	Market approach (guideline public company method)	5.4
Industrials	9.8		Pricing firm	Market approach (guideline public company method)	4.8
Subtotal Level 3 securities	51.7
Pricing exemption securities	3.1
Total Level 3 securities	$	54.8

1 This security was purchased in May 2020.

2 This security was purchased in November 2020.