Liabilities for Outstanding Claims, Losses and Loss Adjustment Expenses (Tables)

12 Months Ended

Dec. 31, 2023

Insurance [Abstract]

Schedule of Liability for Unpaid Losses and Loss Adjustment Expenses

The table below provides a reconciliation of the gross beginning and ending reserve for unpaid losses and loss adjustment expenses.

YEARS ENDED DECEMBER 31	2023			2022			2021
(in millions)
Gross reserve for losses and LAE, beginning of year	$	7,012.6		$	6,447.6		$	6,024.0
Reinsurance recoverable on unpaid losses		1,748.6			1,693.8			1,641.6
Net loss and LAE reserves, beginning of year		5,264.0			4,753.8			4,382.4
Net incurred losses and LAE in respect of losses    occurring in:
Current year		4,150.5			3,656.0			3,205.3
Prior years		(15.9	)		(32.6	)		(71.1	)
Total incurred losses and LAE		4,134.6			3,623.4			3,134.2
Net payments of losses and LAE in respect of losses    occurring in:
Current year		2,037.9			1,578.9			1,464.1
Prior years		1,847.6			1,534.3			1,298.7
Total payments		3,885.5			3,113.2			2,762.8
Net reserve for losses and LAE, end of year		5,513.1			5,264.0			4,753.8
Reinsurance recoverable on unpaid losses		1,795.0			1,748.6			1,693.8
Gross reserve for losses and LAE, end of year	$	7,308.1		$	7,012.6		$	6,447.6

Schedule of (Favorable)/Unfavorable Loss and LAE Reserve Development

The following table provides a summary of (favorable) unfavorable loss and LAE reserve development.

YEARS ENDED DECEMBER 31	2023			2022			2021
(in millions)
Core Commercial	$	(2.0	)	$	(27.6	)	$	(27.5	)
Specialty		(57.1	)		(28.2	)		(18.5	)
Personal Lines		40.9			22.0			(26.1	)
Other		2.3			1.2			1.0
Total loss and LAE reserve development, including catastrophes	$	(15.9	)	$	(32.6	)	$	(71.1	)

Schedule of Carried Reserves

The table below summarizes the gross, ceded and net reserves for losses and LAE and reconciles to the incurred claims development in the following section. Within the Core Commercial segment, commercial multiple peril includes small commercial umbrella policies sold as an endorsement, and general liability and umbrella - occurrence which includes workers’ compensation excess coverages.

YEARS ENDED DECEMBER 31	2023							2022
(in millions)	Gross		Ceded			Net		Gross		Ceded			Net
Commercial multiple peril	$	1,620.3	$	(200.8	)	$	1,419.5	$	1,609.1	$	(185.2	)	$	1,423.9
Workers’ compensation		724.1		(126.5	)		597.6		719.1		(125.2	)		593.9
Commercial automobile liability		491.2		(23.9	)		467.3		469.7		(21.8	)		447.9
General liability and umbrella - occurrence		519.2		(187.0	)		332.2		418.7		(121.8	)		296.9
Other core commercial		113.6		(33.3	)		80.3		134.3		(54.2	)		80.1
Total Core Commercial		3,468.4		(571.5	)		2,896.9		3,350.9		(508.2	)		2,842.7
Specialty property & casualty		861.6		(296.2	)		565.4		820.6		(278.8	)		541.8
General liability - claims made		406.9		(22.4	)		384.5		381.1		(18.7	)		362.4
Other specialty		357.0		(27.6	)		329.4		396.4		(66.5	)		329.9
Total Specialty		1,625.5		(346.2	)		1,279.3		1,598.1		(364.0	)		1,234.1
Personal automobile liability		1,621.9		(822.4	)		799.5		1,566.7		(820.6	)		746.1
Homeowners		377.4		(1.7	)		375.7		312.3		(2.8	)		309.5
Other personal		149.5		(2.4	)		147.1		119.1		(1.6	)		117.5
Total Personal Lines		2,148.8		(826.5	)		1,322.3		1,998.1		(825.0	)		1,173.1
Total Other		65.4		(50.8	)		14.6		65.5		(51.4	)		14.1
Total loss and LAE reserves	$	7,308.1	$	(1,795.0	)	$	5,513.1	$	7,012.6	$	(1,748.6	)	$	5,264.0

Schedule of Incurred Claims Development

Core Commercial - commercial multiple peril
($ in millions)																	As of
Incurred Losses and ALAE, Net of Reinsurance																	December 31, 2023
YEARS ENDED DECEMBER 31,																			Cumulative
																			Incurred
Accident	2016		2017		2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2016	$	398.2	$	402.5	$	401.0	$	400.0	$	400.1	$	396.7	$	397.2	$	401.3	$	6.5		14,426
2017				473.9		481.1		487.5		491.5		494.0		493.6		494.8		13.4		15,377
2018						511.1		495.6		489.5		490.6		495.8		499.7		19.1		15,861
2019								520.2		527.0		533.1		542.6		540.2		30.5		14,895
2020										562.1		546.7		531.5		514.9		45.8		12,989
2021												673.5		658.7		655.1		73.3		14,771
2022														748.1		749.2		145.1		13,903
2023																698.3		266.5		11,956
Total															$	4,553.5
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2016		2017		2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2016	$	128.7	$	215.2	$	261.9	$	306.8	$	331.8	$	347.7	$	365.4	$	374.3
2017				157.2		264.1		328.8		377.6		414.5		435.6		448.3
2018						165.7		274.1		326.4		362.9		403.6		429.5
2019								156.5		288.5		348.7		396.3		444.5
2020										200.8		318.6		364.2		401.0
2021												245.1		392.6		450.0
2022														198.2		441.2
2023																240.5
Total																3,229.3
Total reserves for 2016 – 2023 accident years (incurred - paid)																1,324.2
Total reserves for 2015 and prior accident years																72.0
Unallocated loss adjustment expense																23.3
Net reserves at December 31, 2023															$	1,419.5

Core Commercial - workers’ compensation
($ in millions)																					As of
Incurred Losses and ALAE, Net of Reinsurance																					December 31, 2023
YEARS ENDED DECEMBER 31,																							Cumulative
																							Incurred
Accident	2014		2015		2016		2017		2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2014	$	143.5	$	138.0	$	125.8	$	124.3	$	123.1	$	120.7	$	118.2	$	116.4	$	112.9	$	110.5	$	5.7		8,818
2015				157.0		136.0		132.1		125.8		122.2		119.0		116.3		113.8		110.0		7.8		8,921
2016						158.9		152.8		139.9		133.5		128.3		124.9		122.3		118.3		6.2		12,836
2017								159.6		148.7		139.9		136.7		132.4		129.6		125.7		8.2		13,443
2018										165.2		161.3		152.6		150.8		149.2		145.8		13.1		15,037
2019												170.5		165.0		162.9		163.2		159.5		14.8		15,451
2020														167.1		166.8		150.6		142.4		16.0		12,116
2021																178.5		180.8		175.5		17.1		14,510
2022																		198.5		205.9		32.4		15,056
2023																				202.3		64.8		13,204
Total																			$	1,495.9
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2014		2015		2016		2017		2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2014	$	25.7	$	58.5	$	75.3	$	85.0	$	89.8	$	93.7	$	96.2	$	97.6	$	98.5	$	98.9
2015				24.2		55.0		72.2		81.8		86.2		89.1		91.2		93.2		94.0
2016						29.2		67.0		84.4		93.3		97.2		100.1		102.1		103.5
2017								28.5		63.7		82.0		92.7		99.0		102.6		106.2
2018										32.2		72.0		91.7		104.2		112.0		117.8
2019												30.4		75.7		102.4		116.2		124.5
2020														28.8		71.4		91.8		102.9
2021																40.6		85.3		109.4
2022																		41.4		101.8
2023																				48.8
Total																				1,007.8
Total reserves for 2014 – 2023 accident years (incurred - paid)																				488.1
Total reserves for 2013 and prior accident years																				90.5
Unallocated loss adjustment expense and other																				19.0
Net reserves at December 31, 2023																			$	597.6

Core Commercial - commercial automobile liability
($ in millions)															As of
Incurred Losses and ALAE, Net of Reinsurance															December 31, 2023
YEARS ENDED DECEMBER 31,																	Cumulative
																	Incurred
Accident	2017		2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2017	$	146.3	$	155.6	$	164.3	$	169.4	$	175.6	$	176.0	$	176.8	$	1.4		10,916
2018				170.1		157.6		162.9		171.5		176.1		178.2		6.2		10,611
2019						161.0		167.9		169.7		174.6	181.4			12.9		9,803
2020								153.2		141.5		140.2		134.5		17.4		5,890
2021										154.1		156.5		146.1		33.9		6,134
2022												157.5		173.3		66.7		6,021
2023													171.5			109.3		5,550
Total													$	1,161.8
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2017		2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2017	$	24.9	$	64.8	$	95.5	$	125.8	$	144.4	$	160.9	$	168.3
2018				26.8		52.7		83.2		114.5		142.7		156.0
2019						27.1		64.5		94.8		126.5		147.9
2020								21.0		42.1		71.4		96.3
2021										17.7		45.2		73.7
2022												18.9		53.0
2023														23.7
Total														718.9
Total reserves for 2017 – 2023 accident years (incurred - paid)														442.9
Total reserves for 2016 and prior accident years														19.6
Unallocated loss adjustment expense														4.8
Net reserves at December 31, 2023													$	467.3

Core Commercial - general liability and umbrella - occurrence
($ in millions)																					As of
Incurred Losses and ALAE, Net of Reinsurance																					December 31, 2023
YEARS ENDED DECEMBER 31,																							Cumulative
																							Incurred
Accident	2014		2015		2016		2017		2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2014	$	70.7	$	48.9	$	57.9	$	60.8	$	53.8	$	54.0	$	53.4	$	54.0	$	54.0	$	55.6	$	1.4		1,448
2015				66.6		57.9		58.6		53.8		52.1		50.5		49.1		45.5		43.9		1.7		1,305
2016						58.5		61.0		57.8		55.8		53.7		54.5		54.2		59.2		3.1		1,207
2017								58.2		67.1		66.3		63.0		62.9		61.0		60.8		5.8		1,030
2018										58.8		61.1		60.3		63.3		63.2		65.0		11.9		960
2019												58.9		60.0		60.3		69.3		73.7		14.3		851
2020														56.2		58.9		53.4		52.1		20.1		552
2021																58.3		70.0		73.7		35.9		497
2022																		63.3		76.6		47.6		487
2023																				72.2		58.7		397
Total																			$	632.8
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2014		2015		2016		2017		2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2014	$	1.6	$	7.9	$	17.2	$	30.3	$	38.2	$	45.5	$	46.0	$	47.4	$	48.4	$	51.1
2015				1.4		7.5		14.1		25.5		32.6		37.3		38.3		40.7		40.2
2016						0.7		7.3		14.8		25.3		31.7		34.4		38.7		52.0
2017								2.3		9.0		19.3		27.1		33.9		42.6		46.8
2018										1.0		4.4		18.8		27.2		38.1		40.7
2019												4.3		8.7		16.5		28.2		38.2
2020														2.1		9.2		11.9		17.8
2021																1.5		6.6		17.3
2022																		0.4		9.3
2023																				5.4
Total																				318.8
Total reserves for 2014 – 2023 accident years (incurred - paid)																				314.0
Total reserves for 2013 and prior accident years																				15.0
Unallocated loss adjustment expense and other																				3.2
Net reserves at December 31, 2023																			$	332.2

Specialty property & casualty
($ in millions)															As of
Incurred Losses and ALAE, Net of Reinsurance															December 31, 2023
YEARS ENDED DECEMBER 31,																	Cumulative
																	Incurred
Accident	2017		2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2017	$	189.6	$	185.3	$	190.1	$	193.9	$	195.6	$	199.1	$	198.1	$	7.1		6,850
2018				193.0		194.1		193.7		190.2		191.1		191.1		9.8		6,399
2019						212.2		209.4		225.7		237.1		236.8		18.4		6,480
2020								181.1		170.8		164.9		169.5		19.8		5,235
2021										202.9		213.9		210.2		41.7		5,868
2022												218.3		215.3		67.1		5,487
2023														229.7		116.2		3,973
Total													$	1,450.7
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2017		2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2017	$	55.5	$	102.6	$	125.9	$	138.7	$	155.6	$	168.5	$	177.3
2018				56.0		107.9		124.9		140.3		158.6		170.4
2019						71.5		113.9		136.5		164.9		187.1
2020								40.4		84.0		101.2		121.9
2021										59.2		106.6		125.9
2022												60.7		106.5
2023														61.1
Total														950.2
Total reserves for 2017 – 2023 accident years (incurred - paid)														500.5
Total reserves for 2016 and prior accident years														44.6
Unallocated loss adjustment expense														20.3
Net reserves at December 31, 2023													$	565.4

Specialty - general liability - claims made
($ in millions)															As of
Incurred Losses and ALAE, Net of Reinsurance															December 31, 2023
YEARS ENDED DECEMBER 31,																	Cumulative
																	Incurred
Accident	2017		2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2017	$	99.1	$	100.6	$	96.1	$	94.1	$	92.5	$	93.6	$	94.1	$	1.9		1,047
2018				112.2		117.8		121.2		121.7		121.6		121.7		4.8		1,170
2019						119.8		119.5		125.6		127.6		126.7		7.1		1,213
2020								137.3		134.2		123.3		119.1		10.0		1,295
2021										148.2		144.8		134.6		32.3		1,194
2022												162.3		149.0		59.4		1,234
2023														170.5		98.8		2,530
Total													$	915.7
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2017		2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2017	$	12.1	$	40.9	$	65.5	$	74.8	$	81.0	$	86.3	$	89.3
2018				14.4		50.3		78.9		93.6		102.9		112.0
2019						16.5		53.3		77.0		95.4		107.4
2020								16.8		50.6		75.0		89.4
2021										15.8		49.9		76.7
2022												18.1		54.0
2023														17.9
Total														546.7
Total reserves for 2017 – 2023 accident years (incurred - paid)														369.0
Total reserves for 2016 and prior accident years														8.5
Unallocated loss adjustment expense														7.0
Net reserves at December 31, 2023													$	384.5

Personal automobile liability
($ in millions)													As of
Incurred Losses and ALAE, Net of Reinsurance													December 31, 2023
YEARS ENDED DECEMBER 31,															Cumulative
															Incurred
Accident	2018		2019		2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2018	$	394.2	$	395.3	$	400.3	$	406.7	$	409.3	$	412.2	$	5.4		43,182
2019				431.2		431.8		436.1		438.9		443.5		7.2		42,513
2020						378.0		347.0		312.3		307.0		13.7		26,449
2021								407.2		411.6		408.5		35.1		30,591
2022										441.9		458.6		90.8		33,237
2023												489.9		200.3		32,736
Total											$	2,519.7
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2018		2019		2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		2023
2018	$	121.7	$	237.2	$	307.4	$	353.1	$	382.8	$	397.9
2019				131.0		262.2		336.6		385.1		413.3
2020						95.9		179.2		231.8		267.6
2021								106.4		225.9		304.4
2022										117.2		255.0
2023												143.1
Total												1,781.3
Total reserves for 2018 – 2023 accident years (incurred - paid)												738.4
Total reserves for 2017 and prior accident years												44.0
Unallocated loss adjustment expense												17.1
Net reserves at December 31, 2023											$	799.5

Homeowners
($ in millions)									As of
Incurred Losses and ALAE, Net of Reinsurance									December 31, 2023
YEARS ENDED DECEMBER 31,											Cumulative
											Incurred
Accident	2020		2021		2022						Claim
Year	Unaudited		Unaudited		Unaudited		2023		IBNR		Count
2020	$	418.8	$	423.3	$	424.9	$	427.7	$	3.0		35,333
2021				461.4		489.9		487.9		5.1		39,172
2022						548.5		557.0		10.6		34,989
2023								874.4		185.1		44,865
Total							$	2,347.0
Cumulative Paid Losses and ALAE, Net of Reinsurance
YEARS ENDED DECEMBER 31,
Accident	2020		2021		2022
Year	Unaudited		Unaudited		Unaudited		2023
2020	$	281.5	$	387.7	$	408.1	$	417.8
2021				306.9		449.1		471.4
2022						324.1		511.7
2023								590.4
Total								1,991.3
Total reserves for 2020 – 2023 accident years (incurred - paid)								355.7
Total reserves for 2019 and prior accident years								13.9
Unallocated loss adjustment expense								6.1
Net reserves at December 31, 2023							$	375.7

Computation of Historical Claims on Paid and Incurred Claims Data, Net of Reinsurance

The following table is information about average historical claims duration as of December 31, 2023. The table is computed based on the paid and incurred claims data, net of reinsurance, for the accident years presented in the preceding claims development tables.

Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance:
Unaudited
	1			2			3			4			5			6			7			8			9			10
Core Commercial - commercial multiple peril		32.9	%		23.9	%		10.7	%		8.9	%		7.7	%		4.5	%		3.5	%		2.2	%
Core Commercial - workers’ compensation		22.1	%		28.7	%		14.8	%		8.4	%		4.5	%		3.1	%		2.2	%		1.4	%		0.8	%		0.4	%
Core Commercial - commercial automobile liability		13.8	%		18.7	%		18.5	%		17.7	%		12.7	%		8.4	%		4.2	%
Core Commercial - general liability and umbrella - occurrence		3.2	%		10.1	%		14.2	%		17.2	%		13.8	%		9.3	%		4.3	%		10.2	%		0.3	%		4.9	%
Specialty property & casualty		27.8	%		23.1	%		9.9	%		9.7	%		9.2	%		6.3	%		4.4	%
Specialty - general liability - claims made		12.3	%		27.8	%		21.7	%		12.1	%		7.9	%		6.6	%		3.2	%
Personal automobile liability		28.5	%		28.8	%		17.5	%		11.2	%		6.8	%		3.7	%
Homeowners		63.6	%		29.2	%		4.7	%		2.3	%