Claim and Claim Adjustment Expense Reserves (Tables)

12 Months Ended

Dec. 31, 2023

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration insurance contracts, reconciliation of claims development to liability

The table below reconciles the net liability for unpaid claim and claim adjustment expenses to the amount presented on the Consolidated Balance Sheets.

As of December 31
(In millions)	2023
Net liability for unpaid claim and claim adjustment expenses:
Specialty	$	5,916
Commercial	9,021
International	2,276
Life & Group (1)	582
Corporate & Other	368
Total net claim and claim adjustment expenses	18,163
Reinsurance receivables: (2)
Specialty	1,215
Commercial	1,082
International	433
Life & Group	93
Corporate & Other (3)	2,318
Total reinsurance receivables	5,141
Total gross liability for unpaid claim and claim adjustment expenses	$	23,304

(1) The Life & Group segment amounts are related to unfunded structured settlements arising from short-duration contracts.

(2) Reinsurance receivables presented are gross of the allowance for uncollectible reinsurance and do not include reinsurance receivables related to paid losses.

(3) The Corporate & Other Reinsurance receivables are primarily related to A&EP claims covered under the A&EP Loss Portfolio Transfer (LPT).

Schedule of liability for unpaid claims and claims adjustment expense

The following table presents a reconciliation between beginning and ending claim and claim adjustment expense reserves.

As of or for the years ended December 31
(In millions)	2023		2022 (1)		2021 (1)
Reserves, beginning of year:
Gross	$	22,120	$	21,269	$	19,862
Ceded	5,191		4,969		4,005
Net reserves, beginning of year	16,929		16,300		15,857
Reduction of net reserves due to Excess Workers' Compensation Loss Portfolio Transfer	—		—		(632)
Net incurred claim and claim adjustment expenses:
Provision for insured events of current year	5,667		5,181		5,021
Increase (decrease) in provision for insured events of prior years	48		(32)		15
Amortization of discount	44		44		48
Total net incurred (2)	5,759		5,193		5,084
Net payments attributable to:
Current year events	(922)		(821)		(933)
Prior year events	(3,679)		(3,481)		(3,016)
Total net payments	(4,601)		(4,302)		(3,949)
Foreign currency translation adjustment and other	76		(262)		(60)
Net reserves, end of year	18,163		16,929		16,300
Ceded reserves, end of year	5,141		5,191		4,969
Gross reserves, end of year	$	23,304	$	22,120	$	21,269

(1) In conjunction with the Company's adoption of ASU 2018-12, at January 1, 2023, long-term care reserves for policyholders currently receiving benefits were reclassified from Claim and claim adjustment expenses into Future policy benefits and this change was applied retrospectively as of January 1, 2021. See Note A to the Consolidated Financial Statements for additional information.

(2) Total net incurred does not agree to Insurance claims and policyholders' benefits as reflected on the Consolidated Statements of Operations due to amounts related to retroactive reinsurance deferred gain accounting, the loss on the Excess Workers' Compensation LPT (EWC LPT) and uncollectible reinsurance, which are not reflected in the table above.

Gross and net carried claim and claim adjustment expense reserves

The following tables present the gross and net carried reserves.

December 31, 2023	Specialty		Commercial		International		Life & Group		Corporate & Other		Total
(In millions)
Gross Case Reserves	$	1,604	$	3,291	$	864	$	626	$	1,353	$	7,738
Gross IBNR Reserves	5,527		6,812		1,845		49		1,333		15,566
Total Gross Carried Claim and Claim Adjustment Expense Reserves	$	7,131	$	10,103	$	2,709	$	675	$	2,686	$	23,304
Net Case Reserves	$	1,392	$	2,878	$	708	$	556	$	129	$	5,663
Net IBNR Reserves	4,524		6,143		1,568		26		239		12,500
Total Net Carried Claim and Claim Adjustment Expense Reserves	$	5,916	$	9,021	$	2,276	$	582	$	368	$	18,163

December 31, 2022	Specialty		Commercial		International		Life & Group(1)		Corporate & Other		Total
(In millions)
Gross Case Reserves	$	1,529	$	3,156	$	817	$	647	$	1,428	$	7,577
Gross IBNR Reserves	5,349		6,239		1,586		48		1,321		14,543
Total Gross Carried Claim and Claim Adjustment Expense Reserves	$	6,878	$	9,395	$	2,403	$	695	$	2,749	$	22,120
Net Case Reserves	$	1,310	$	2,809	$	686	$	567	$	137	$	5,509
Net IBNR Reserves	4,253		5,621		1,317		27		202		11,420
Total Net Carried Claim and Claim Adjustment Expense Reserves	$	5,563	$	8,430	$	2,003	$	594	$	339	$	16,929

(1) In conjunction with the Company's adoption of ASU 2018-12, at January 1, 2023, long-term care reserves for policyholders currently receiving benefits were reclassified from Claim and claim adjustment expenses into Future policy benefits and this change was applied retrospectively as of January 1, 2021. See Note A to the Consolidated Financial Statements for additional information.

Net prior year development

The following table presents development recorded for the Specialty, Commercial, International and Corporate & Other segments.

Years ended December 31
(In millions)	2023		2022		2021
Pretax (favorable) unfavorable development:
Specialty	$	(14)	$	(40)	$	(45)
Commercial	(22)		(43)		(6)
International	13		(13)		2
Corporate & Other	71		64		60
Total pretax (favorable) unfavorable development	$	48	$	(32)	$	11

Impact of loss portfolio transfer on the consolidated statement of operations

The following table presents the impact of the Loss Portfolio Transfer on the Consolidated Statements of Operations.

Years ended December 31
(In millions)	2023		2022		2021
Additional amounts ceded under LPT:
Net A&EP adverse development before consideration of LPT	$	86	$	92	$	143
Provision for uncollectible third-party reinsurance on A&EP	—		(5)		(5)
Total additional amounts ceded under LPT	86		87		138
Retroactive reinsurance benefit recognized	(94)		(91)		(107)
Pretax impact of deferred retroactive reinsurance	$	(8)	$	(4)	$	31

Specialty

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration insurance contracts, reconciliation of claims development to liability

The table below provides the line of business composition of the net liability for unpaid claim and claim adjustment expenses for the Specialty segment.

As of December 31
(In millions)	2023
Net liability for unpaid claim and claim adjustment expenses:
Medical Professional Liability	$	1,460
Other Professional Liability and Management Liability	3,897
Surety	468
Warranty	28
Other	63
Total net liability for unpaid claim and claim adjustment expenses	$	5,916

Net prior year claim and allocated claim adjustment expense reserve development

The following table presents further detail of the development recorded for the Specialty segment.

Years ended December 31
(In millions)	2023		2022		2021
Pretax (favorable) unfavorable development:
Medical Professional Liability	$	5	$	18	$	23
Other Professional Liability and Management Liability	37		50		24
Surety	(43)		(83)		(73)
Warranty	(11)		(21)		(14)
Other	(2)		(4)		(5)
Total pretax (favorable) unfavorable development	$	(14)	$	(40)	$	(45)

Commercial

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration insurance contracts, reconciliation of claims development to liability

The table below provides the line of business composition of the net liability for unpaid claim and claim adjustment expenses for the Commercial segment.

As of December 31
(In millions)	2023
Net Claim and claim adjustment expenses:
Commercial Auto	$	926
General Liability	3,780
Workers' Compensation	3,645
Property and Other	670
Total net liability for claim and claim adjustment expenses	$	9,021

Net prior year claim and allocated claim adjustment expense reserve development

The following table presents further detail of the development recorded for the Commercial segment.

Years ended December 31
(In millions)	2023		2022		2021
Pretax (favorable) unfavorable development:
Commercial Auto	$	33	$	49	$	53
General Liability	149		67		15
Workers' Compensation	(203)		(152)		(82)
Property and Other	(1)		(7)		8
Total pretax (favorable) unfavorable development	$	(22)	$	(43)	$	(6)

International

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration insurance contracts, reconciliation of claims development to liability

The table below provides the composition of the net liability for unpaid claim and claim adjustment expenses for the International segment.

As of December 31
(In millions)	2023
Net Claim and claim adjustment expenses:
International excluding Hardy	$	1,655
Hardy	621
Total net liability for claim and claim adjustment expenses	$	2,276

Net prior year claim and allocated claim adjustment expense reserve development

The following table presents further detail of the development recorded for the International segment.

Years ended December 31
(In millions)	2023		2022		2021
Pretax (favorable) unfavorable development:
Commercial	$	(18)	$	(10)	$	(35)
Specialty	35		(4)		36
Other	(4)		1		1
Total pretax (favorable) unfavorable development	$	13	$	(13)	$	2

CNAF Consolidated

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Schedule of historical claims duration

The table below presents information about average historical claims duration as of December 31, 2023 and is presented as required supplementary information, which is unaudited.

Average Annual Percentage Payout of Ultimate Net Incurred Claim and Allocated Claim Adjustment Expenses in Year:
	1		2		3		4		5		6		7		8		9		10
Specialty
Medical Professional Liability	3.7	%	16.4	%	22.1	%	17.2	%	12.4	%	9.1	%	4.8	%	2.9	%	1.2	%	1.1	%
Other Professional Liability and Management Liability	6.5	%	19.8	%	19.3	%	14.9	%	10.9	%	6.3	%	4.9	%	6.0	%	1.7	%	0.5	%
Surety(1)	17.7	%	46.6	%	17.7	%	3.4	%	2.2	%	5.2	%	(1.7)	%	(0.8)	%	(0.1)	%	—	%
Commercial
Commercial Auto	25.2	%	22.2	%	18.2	%	14.3	%	10.6	%	4.9	%	2.0	%	0.7	%	0.3	%	0.5	%
General Liability	3.6	%	12.8	%	16.3	%	17.4	%	14.4	%	9.1	%	5.9	%	5.3	%	2.2	%	2.7	%
Workers' Compensation	16.0	%	22.9	%	13.8	%	8.8	%	6.0	%	3.2	%	2.1	%	1.3	%	1.2	%	1.7	%
International
International - Excluding Hardy	16.9	%	21.8	%	9.8	%	6.5	%	5.9	%	7.4	%	8.4	%	2.6	%	2.8	%	1.7	%
International - Hardy	18.0	%	31.3	%	13.7	%	7.5	%	4.7	%	4.9	%	0.5	%	2.3	%	(1.4)	%	—	%

(1) Due to the nature of the Surety business, average annual percentage payout of ultimate net incurred claim and allocated claim adjustment expenses has been calculated using only the payouts of mature accident years presented in the loss reserve development tables.

Hardy | International

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023			IBNR		Cumulative Number of Claims
Accident Year
2014	$	183	$	182	$	175	$	169	$	170	$	170	$	169	$	167	$	166	$	167		$	(1)	8,534
2015			187		177		175		175		173		175		176		178		177			(3)		9,741
2016					227		244		233		223		224		218		219		223			6		10,895
2017							243		252		242		243		251		251		239			(5)		13,294
2018									268		298		302		307		307		324			36		15,366
2019											219		223		217		224		220			25		11,670
2020													210		201		195		192			55		7,036
2021															177		168		154			59		3,831
2022																	190		186			96		2,371
2023																			200			152		1,388
																	Total		$	2,082		$	420

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	56	$	122	$	140	$	150	$	155	$	161	$	162	$	163	$	164	$	164
2015			29		97		128		143		154		162		160		169		163
2016					63		144		171		180		193		204		205		208
2017							53		150		183		205		212		224		229
2018									55		170		200		231		249		270
2019											43		102		140		157		167
2020													27		77		103		118
2021															13		44		68
2022																	23		58
2023																			17
Total																			$	1,462
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	620
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			(8)
Liability for unallocated claim adjustment expenses for accident years presented																			9
Total net liability for unpaid claim and claim adjustment expenses																			$	621

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total(2)
Accident Year
2014	$	(1)	$	(7)	$	(6)	$	1	$	—	$	(1)	$	(2)	$	(1)	$	1	$	(16)
2015			(10)		(2)		—		(2)		2		1		2		(1)		(10)
2016					17		(11)		(10)		1		(6)		1		4		(4)
2017							9		(10)		1		8		—		(12)		(4)
2018									30		4		5		—		17		56
2019											4		(6)		7		(4)		1
2020													(9)		(6)		(3)		(18)
2021															(9)		(14)		(23)
2022																	(4)		(4)

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

(2) The amounts included in the loss reserve development tables above are presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate fluctuations between calendar years. The amounts included within the table on page 110 presenting the detail of the development recorded within the International segment include the impact of fluctuations in foreign currency exchange rates.

Medical Professional Liability | Specialty

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	450	$	489	$	537	$	530	$	535	$	529	$	527	$	524	$	527	$	525	$	6	19,830
2015			433		499		510		494		488		510		501		498		494		15		18,218
2016					427		487		485		499		508		510		508		514		17		16,169
2017							412		449		458		460		455		460		456		20		15,345
2018									404		429		431		448		470		495		41		15,266
2019											430		445		458		471		469		62		14,409
2020													477		476		455		447		180		11,129
2021															377		376		374		193		9,523
2022																	329		329		206		9,237
2023																			340		281		8,240
																	Total		$	4,443	$	1,021

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	23	$	136	$	258	$	359	$	417	$	472	$	489	$	497	$	504	$	510
2015			22		101		230		313		384		420		444		458		463
2016					18		121		246		339		401		436		460		483
2017							19		107		235		308		355		388		417
2018									21		115		211		290		349		418
2019											17		91		183		280		349
2020													11		61		139		201
2021															11		49		118
2022																	10		57
2023																			14
																	Total		$	3,030
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	1,413
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			22
Liability for unallocated claim adjustment expenses for accident years presented																			25
Total net liability for unpaid claim and claim adjustment expenses																			$	1,460

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total
Accident Year
2014	$	39	$	48	$	(7)	$	5	$	(6)	$	(2)	$	(3)	$	3	$	(2)	$	75
2015			66		11		(16)		(6)		22		(9)		(3)		(4)		61
2016					60		(2)		14		9		2		(2)		6		87
2017							37		9		2		(5)		5		(4)		44
2018									25		2		17		22		25		91
2019											15		13		13		(2)		39
2020													(1)		(21)		(8)		(30)
2021															(1)		(2)		(3)
2022																	—		—
Total net development for the accident years presented above													14		16		9
Total net development for accident years prior to 2014													2		(3)		(4)
Total unallocated claim adjustment expense development													7		5		—
Total													$	23	$	18	$	5

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

Other Professional Liability and Management Liability | Specialty

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	878	$	898	$	885	$	831	$	835	$	854	$	845	$	841	$	842	$	838	$	26	17,585
2015			888		892		877		832		807		813		836		855		858		18		17,454
2016					901		900		900		904		907		891		888		906		39		17,987
2017							847		845		813		791		775		758		746		69		18,199
2018									850		864		869		906		923		941		101		20,038
2019											837		845		856		876		939		100		19,515
2020													930		944		951		945		281		19,437
2021															1,037		1,038		1,009		532		18,259
2022																	1,120		1,112		706		18,165
2023																			1,149		971		16,469
																	Total		$	9,443	$	2,843

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	51	$	223	$	392	$	515	$	647	$	707	$	743	$	787	$	802	$	806
2015			60		234		404		542		612		677		725		794		808
2016					64		248		466		625		701		736		784		826
2017							57		222		394		498		557		596		630
2018									54		282		473		599		706		779
2019											64		263		422		567		699
2020													67		248		400		523
2021															58		217		356
2022																	64		225
2023																			64
																	Total		$	5,716
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	3,727
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			115
Liability for unallocated claim adjustment expenses for accident years presented																			55
Total net liability for unpaid claim and claim adjustment expenses																			$	3,897

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total
Accident Year
2014	$	20	$	(13)	$	(54)	$	4	$	19	$	(9)	$	(4)	$	1	$	(4)	$	(40)
2015			4		(15)		(45)		(25)		6		23		19		3		(30)
2016					(1)		—		4		3		(16)		(3)		18		5
2017							(2)		(32)		(22)		(16)		(17)		(12)		(101)
2018									14		5		37		17		18		91
2019											8		11		20		63		102
2020													14		7		(6)		15
2021															1		(29)		(28)
2022																	(8)		(8)
Total net development for the accident years presented above													49		45		43
Total net development for accident years prior to 2014													(27)		5		(6)
Total unallocated claim adjustment expense development													2		—		—
Total													$	24	$	50	$	37

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

Surety | Specialty

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	123	$	124	$	94	$	69	$	60	$	45	$	45	$	43	$	42	$	41	$	2	5,135
2015			131		131		104		79		63		58		53		45		45		2		5,085
2016					124		124		109		84		67		64		58		43		3		5,565
2017							120		115		103		84		71		66		67		4		5,883
2018									114		108		91		62		56		51		10		6,249
2019											119		112		98		87		82		12		6,152
2020													128		119		81		67		34		4,678
2021															137		129		110		68		4,645
2022																	155		158		116		4,350
2023																			175		167		2,750
																	Total		$	839	$	418

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	7	$	30	$	38	$	36	$	38	$	38	$	39	$	39	$	38	$	38
2015			7		26		38		40		42		44		42		42		43
2016					5		37		45		45		43		43		41		40
2017							23		37		41		46		49		62		62
2018									5		25		34		39		40		41
2019											12		34		44		59		70
2020													4		20		28		33
2021															5		20		35
2022																	12		35
2023																			8
																	Total		$	405
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	434
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			13
Liability for unallocated claim adjustment expenses for accident years presented																			21
Total net liability for unpaid claim and claim adjustment expenses																			$	468

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total
Accident Year
2014	$	1	$	(30)	$	(25)	$	(9)	$	(15)	$	—	$	(2)	$	(1)	$	(1)	$	(82)
2015			—		(27)		(25)		(16)		(5)		(5)		(8)		—		(86)
2016					—		(15)		(25)		(17)		(3)		(6)		(15)		(81)
2017							(5)		(12)		(19)		(13)		(5)		1		(53)
2018									(6)		(17)		(29)		(6)		(5)		(63)
2019											(7)		(14)		(11)		(5)		(37)
2020													(9)		(38)		(14)		(61)
2021															(8)		(19)		(27)
2022																	3		3
Total net development for the accident years presented above													(75)		(83)		(55)
Total net development for accident years prior to 2014													2		—		12
Total unallocated claim adjustment expense development													—		—		—
Total													$	(73)	$	(83)	$	(43)

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

Commercial Auto | Commercial

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	234	$	223	$	212	$	205	$	205	$	201	$	201	$	202	$	201	$	201	$	1	33,633
2015			201		199		190		190		183		181		183		182		184		4		30,430
2016					198		186		186		186		190		195		200		197		4		30,455
2017							199		198		200		221		232		239		241		4		30,947
2018									229		227		227		245		254		255		1		34,333
2019											257		266		289		323		325		10		37,258
2020													310		303		304		298		21		29,142
2021															397		388		390		93		32,918
2022																	437		465		137		36,777
2023																			554		347		34,211
																	Total		$	3,110	$	622

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	64	$	102	$	137	$	166	$	187	$	196	$	198	$	199	$	199	$	200
2015			52		96		130		153		172		175		178		179		180
2016					52		93		126		154		175		185		190		192
2017							58		107		150		178		203		225		232
2018									66		128		175		212		238		249
2019											77		147		203		257		295
2020													71		134		197		246
2021															83		168		240
2022																	112		236
2023																			127
																	Total		$	2,197
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	913
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			4
Liability for unallocated claim adjustment expenses for accident years presented																			9
Total net liability for unpaid claim and claim adjustment expenses																			$	926

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total
Accident Year
2014	$	(11)	$	(11)	$	(7)	$	—	$	(4)	$	—	$	1	$	(1)	$	—	$	(33)
2015			(2)		(9)		—		(7)		(2)		2		(1)		2		(17)
2016					(12)		—		—		4		5		5		(3)		(1)
2017							(1)		2		21		11		7		2		42
2018									(2)		—		18		9		1		26
2019											9		23		34		2		68
2020													(7)		1		(6)		(12)
2021															(9)		2		(7)
2022																	28		28
Total net development for the accident years presented above													53		45		28
Total net development for accident years prior to 2014													—		4		2
Total unallocated claim adjustment expense development													—		—		3
Total													$	53	$	49	$	33

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

General Liability | Commercial

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	653	$	658	$	654	$	631	$	635	$	658	$	659	$	659	$	676	$	679	$	28	28,196
2015			581		576		574		589		600		602		617		625		639		28		24,261
2016					623		659		667		671		673		683		684		704		39		24,803
2017							632		632		632		634		630		652		690		36		22,471
2018									653		644		646		639		650		679		129		20,425
2019											680		682		682		691		720		174		19,647
2020													723		722		726		736		347		14,593
2021															782		784		793		401		15,121
2022																	929		928		676		15,754
2023																			1,071		963		11,633
																	Total		$	7,639	$	2,821

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	31	$	119	$	247	$	376	$	481	$	547	$	569	$	607	$	624	$	642
2015			19		110		230		357		446		501		530		561		573
2016					32		163		279		407		481		524		582		620
2017							23		118		250		399		471		553		606
2018									33		107		228		307		428		491
2019											25		98		181		322		455
2020													23		99		192		280
2021															26		140		262
2022																	29		123
2023																			33
																	Total		$	4,085
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	3,554
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			162
Liability for unallocated claim adjustment expenses for accident years presented																			64
Total net liability for unpaid claim and claim adjustment expenses																			$	3,780

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total
Accident Year
2014	$	5	$	(4)	$	(23)	$	4	$	23	$	1	$	—	$	17	$	3	$	26
2015			(5)		(2)		15		11		2		15		8		14		58
2016					36		8		4		2		10		1		20		81
2017							—		—		2		(4)		22		38		58
2018									(9)		2		(7)		11		29		26
2019											2		—		9		29		40
2020													(1)		4		10		13
2021															2		9		11
2022																	(1)		(1)
Total net development for the accident years presented above													13		74		151
Total net development for accident years prior to 2014													—		(7)		(2)
Total unallocated claim adjustment expense development													2		—		—
Total													$	15	$	67	$	149

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

Workers' Compensation | Commercial

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	467	$	480	$	479	$	452	$	450	$	446	$	439	$	448	$	430	$	419	$	70	33,550
2015			422		431		406		408		394		382		372		353		334		59		31,904
2016					426		405		396		382		366		355		331		308		56		31,994
2017							440		432		421		400		402		399		398		78		33,142
2018									450		440		428		415		415		404		74		34,886
2019											452		449		437		436		419		78		34,349
2020													477		466		446		414		135		29,454
2021															468		454		432		146		30,066
2022																	497		489		198		33,229
2023																			555		344		31,549
																	Total		$	4,172	$	1,238

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	61	$	159	$	215	$	258	$	282	$	290	$	297	$	306	$	312	$	319
2015			51		131		180		212		231		243		251		256		259
2016					53		129		169		198		219		227		234		235
2017							63		151		207		243		265		279		287
2018									68		163		229		259		280		298
2019											71		169		223		262		291
2020													65		147		200		228
2021															67		164		222
2022																	79		192
2023																			87
																	Total		$	2,418
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	1,754
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			1,842
Other (2)																			(23)
Liability for unallocated claim adjustment expenses for accident years presented																			72
Total net liability for unpaid claim and claim adjustment expenses																			$	3,645

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total
Accident Year
2014	$	13	$	(1)	$	(27)	$	(2)	$	(4)	$	(7)	$	9	$	(18)	$	(11)	$	(48)
2015			9		(25)		2		(14)		(12)		(10)		(19)		(19)		(88)
2016					(21)		(9)		(14)		(16)		(11)		(24)		(23)		(118)
2017							(8)		(11)		(21)		2		(3)		(1)		(42)
2018									(10)		(12)		(13)		—		(11)		(46)
2019											(3)		(12)		(1)		(17)		(33)
2020													(11)		(20)		(32)		(63)
2021															(14)		(22)		(36)
2022																	(8)		(8)
Total net development for the accident years presented above													(46)		(99)		(144)
Adjustment for development on a discounted basis													2		(3)		(2)
Total net development for accident years prior to 2014													(38)		(60)		(63)
Total unallocated claim adjustment expense development													—		10		6
Total													$	(82)	$	(152)	$	(203)

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

(2) Other includes the effect of discounting lifetime claim reserves.

Excluding Hardy | International

Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]

Short-duration contracts net incurred claims and allocated claim adjustment expenses

Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year																				As of December 31, 2023
(In millions, except reported claims data)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		IBNR		Cumulative Number of Claims
Accident Year
2014	$	276	$	291	$	291	$	279	$	272	$	289	$	290	$	283	$	286	$	288	$	15	25,130
2015			289		304		303		286		280		283		285		285		281		19		23,608
2016					284		302		288		285		276		290		292		309		36		18,079
2017							299		363		383		376		371		360		393		39		18,841
2018									367		385		389		388		401		411		48		21,327
2019											342		355		352		360		362		61		18,993
2020													381		372		362		347		107		15,744
2021															408		397		375		162		15,136
2022																	428		438		227		11,899
2023																			478		359		7,869
																	Total		$	3,682	$	1,073

Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense

Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.

As of December 31	Calendar Year
(In millions)	2014(1)		2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023
Accident Year
2014	$	51	$	121	$	149	$	166	$	182	$	203	$	236	$	241	$	248	$	253
2015			56		132		162		182		204		219		230		237		246
2016					66		131		158		180		192		214		226		237
2017							64		146		186		214		237		264		321
2018									89		166		212		242		266		308
2019											73		164		201		224		247
2020													60		128		162		178
2021															56		124		154
2022																	46		138
2023																			46
Total																			$	2,128
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented																			$	1,554
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014																			64
Liability for unallocated claim adjustment expenses for accident years presented																			37
Total net liability for unpaid claim and claim adjustment expenses																			$	1,655

Short-duration contracts reserve development

Net strengthening (releases) of prior accident year reserves is presented in the following table.

For the years ended December 31	Calendar Year
(In millions)	2015(1)		2016(1)		2017(1)		2018(1)		2019(1)		2020(1)		2021(1)		2022(1)		2023		Total (2)
Accident Year
2014	$	15	$	—	$	(12)	$	(7)	$	17	$	1	$	(7)	$	3	$	2	$	12
2015			15		(1)		(17)		(6)		3		2		—		(4)		(8)
2016					18		(14)		(3)		(9)		14		2		17		25
2017							64		20		(7)		(5)		(11)		33		94
2018									18		4		(1)		13		10		44
2019											13		(3)		8		2		20
2020													(9)		(10)		(15)		(34)
2021															(11)		(22)		(33)
2022																	10		10

(1) Data presented for these calendar years is required supplemental information, which is unaudited.

(2) The amounts included in the loss reserve development tables above are presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate fluctuations between calendar years. The amounts included within the table on page 110 presenting the detail of the development recorded within the International segment include the impact of fluctuations in foreign currency exchange rates.