(Tables)

12 Months Ended

Dec. 31, 2019

Insurance [Abstract]

Consolidated Property Casualty Loss And Loss Expense Reserves

This table summarizes activity for our consolidated property casualty loss and loss expense reserves:

(Dollars in millions)	Years ended December 31,
	2019			2018			2017
Gross loss and loss expense reserves, January 1	$	5,646		$	5,219		$	5,035
Less reinsurance recoverable	238			187			298
Net loss and loss expense reserves, January 1	5,408			5,032			4,737
Net loss and loss expense reserves related to acquisition of Cincinnati Global at   February 28, 2019	246			—			—
Net incurred loss and loss expenses related to:
Current accident year	3,600			3,390			3,257
Prior accident years	(248		)	(167		)	(119		)
Total incurred	3,352			3,223			3,138
Net paid loss and loss expenses related to:
Current accident year	1,462			1,391			1,404
Prior accident years	1,798			1,456			1,439
Total paid	3,260			2,847			2,843
Net loss and loss expense reserves, December 31	5,746			5,408			5,032
Plus reinsurance recoverable	342			238			187
Gross loss and loss expense reserves, December 31	$	6,088		$	5,646		$	5,219

Reconciliation of Property casualty Incurred Losses and ALAE and Paid Losses and ALAE Development Information

The following table provides a reconciliation of the property casualty incurred losses and allocated loss adjustment expenses (ALAE) development and paid losses and ALAE development information at December 31, 2019.

(Dollars in millions)	Cumulative incurred losses and ALAE as reported within the triangles, net of reinsurance		Cumulative paid losses and ALAE as reported within the triangles, net of reinsurance		Liabilities for loss and ALAE for accident years not presented in the triangles, net of reinsurance		Total liabilities for loss and ALAE, net of reinsurance		Reinsurance recoverable on unpaid losses		Total liabilities for gross loss and loss expense reserves
Commercial casualty	$	4,910	$	2,863	$	88	$	2,135	$	30	$	2,165
Workers' compensation	2,061		1,433		295		923		64		987
Commercial auto	2,200		1,566		15		649		5		654
Commercial property	2,739		2,469		13		283		111		394
Personal auto	1,933		1,659		6		280		33		313
Homeowner	1,779		1,621		2		160		21		181
Excess and surplus	658		333		1		326		8		334
Other lines											771
Total liabilities for loss and ALAE reserves											5,799
Unallocated loss adjustment expense reserves											289
Gross loss and loss expense reserves											$	6,088

Schedule of Incurred and Paid Losses and ALAE Development by Accident Year

The following table shows the commercial auto incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)											As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,												Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2015		2016		2017		2018		2019
2015	$	374	$	384	$	394	$	401	$	400		$	3	51
2016			417		430		450		463			7		53
2017					451		441		443			27		51
2018							453		442			72		49
2019									452			133		42
Total									$	2,200
Cumulative paid losses and ALAE, net of reinsurance
2015	$	173	$	244	$	303	$	349	$	375
2016			184		273		350		408
2017					187		266		334
2018							184		266
2019									183
Total									1,566
All outstanding liabilities before 2015, net of reinsurance									15
Liabilities for loss and ALAE, net of reinsurance									$	649

The following table shows the commercial casualty incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)																					As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,																						Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019
2010	$	495	$	394	$	378	$	349	$	347	$	348	$	349	$	343	$	341	$	336		$	11	20
2011			466		404		377		377		375		380		366		365		368			11		19
2012					466		414		417		394		394		404		399		397			14		18
2013							448		443		431		416		413		407		391			31		20
2014									503		496		479		476		479		465			34		21
2015											533		526		529		516		508			78		21
2016													563		574		557		555			120		21
2017															610		597		577			160		20
2018																	650		641			272		20
2019																			672			440		15
Total																			$	4,910
Cumulative paid losses and ALAE, net of reinsurance
2010	$	33	$	92	$	159	$	203	$	256	$	285	$	300	$	314	$	318	$	321
2011			27		93		149		227		266		298		315		325		337
2012					27		88		170		232		288		330		346		364
2013							35		90		159		232		286		312		337
2014									34		97		172		287		338		390
2015											38		108		200		287		362
2016													46		126		228		331
2017															48		122		234
2018																	44		148
2019																			39
Total																			2,863
All outstanding liabilities before 2010, net of reinsurance																			88
Liabilities for loss and ALAE, net of reinsurance																			$	2,135

The following table shows the excess and surplus lines incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)																			As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,																				Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2011		2012		2013		2014		2015		2016		2017		2018		2019
2011	$	48	$	47	$	44	$	38	$	36	$	35	$	35	$	34	$	34		$	—	1
2012			67		56		49		40		37		36		35		36			1		1
2013					74		64		54		45		42		41		41			1		2
2014							95		82		75		64		60		59			6		2
2015									96		81		73		67		65			8		2
2016											93		87		84		82			14		3
2017													104		95		95			26		3
2018															116		109			44		3
2019																	137			83		2
Total																	$	658
Cumulative paid losses and ALAE, net of reinsurance
2011	$	8	$	14	$	23	$	27	$	30	$	32	$	34	$	33	$	33
2012			9		15		19		25		29		31		32		33
2013					7		12		20		27		32		34		37
2014							9		17		27		37		43		48
2015									8		19		29		41		51
2016											10		21		39		51
2017													11		23		41
2018															11		26
2019																	13
Total																	333
All outstanding liabilities before 2011, net of reinsurance																	1
Liabilities for loss and ALAE, net of reinsurance																	$	326

The following table shows the personal auto incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)											As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,												Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2015		2016		2017		2018		2019
2015	$	343	$	356	$	356	$	360	$	361		$	—	108
2016			383		384		386		384			—		110
2017					412		394		391			—		109
2018							424		398			18		111
2019									399			54		96
Total									$	1,933
Cumulative paid losses and ALAE, net of reinsurance
2015	$	229	$	292	$	325	$	346	$	354
2016			243		316		351		370
2017					256		324		358
2018							262		327
2019									250
Total									1,659
All outstanding liabilities before 2015 net of reinsurance									6
Liabilities for loss and ALAE, net of reinsurance									$	280

The following table shows the commercial property incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)											As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,												Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2015		2016		2017		2018		2019
2015	$	454	$	414	$	416	$	415	$	414		$	2	17
2016			590		551		541		545			4		17
2017					587		560		556			5		18
2018							630		603			9		18
2019									621			22		15
Total									$	2,739
Cumulative paid losses and ALAE, net of reinsurance
2015	$	279	$	388	$	407	$	411	$	411
2016			358		504		528		539
2017					395		522		547
2018							386		559
2019									413
Total									2,469
All outstanding liabilities before 2015, net of reinsurance									13
Liabilities for loss and ALAE, net of reinsurance									$	283

The following table shows the workers’ compensation incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)																					As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,																						Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019
2010	$	283	$	274	$	248	$	242	$	240	$	239	$	240	$	237	$	236	$	237		$	19	26
2011			284		251		246		242		239		236		231		229		228			17		24
2012					265		245		234		220		213		211		209		208			21		21
2013							264		246		221		212		208		205		202			16		20
2014									261		233		214		203		201		198			18		19
2015											246		220		208		195		179			33		17
2016													230		218		206		188			31		16
2017															218		208		190			56		15
2018																	222		207			65		15
2019																			224			90		13
Total																			$	2,061
Cumulative paid losses and ALAE, net of reinsurance
2010	$	67	$	134	$	164	$	181	$	192	$	198	$	202	$	204	$	207	$	209
2011			65		131		161		177		186		190		192		195		197
2012					62		121		147		162		171		175		178		180
2013							61		119		144		157		164		168		170
2014									56		110		134		148		157		162
2015											47		93		115		129		134
2016													46		97		119		131
2017															45		88		106
2018																	48		95
2019																			49
Total																			1,433
All outstanding liabilities before 2010, net of reinsurance																			295
Liabilities for loss and ALAE, net of reinsurance																			$	923

The following table shows the homeowner incurred and paid losses and ALAE development by accident year. The table also shows the IBNR reserves plus expected development on reported losses and claim frequency:

(Dollars in millions, reported claims in thousands)											As of December 31, 2019
Incurred losses and ALAE, net of reinsurance for the years ended December 31,												Total of incurred but not reported liabilities plus expected development on reported losses		Cumulative number of reported claims
Accident	Unaudited
Year	2015		2016		2017		2018		2019
2015	$	284	$	275	$	275	$	274	$	274		$	—	24
2016			315		304		303		302			—		23
2017					356		383		385			1		26
2018							370		386			6		23
2019									432			39		20
Total									$	1,779
Cumulative paid losses and ALAE, net of reinsurance
2015	$	203	$	260	$	269	$	272	$	273
2016			208		283		295		299
2017					277		356		378
2018							268		368
2019									303
Total									1,621
All outstanding liabilities before 2015, net of reinsurance									2
Liabilities for loss and ALAE, net of reinsurance									$	160

Schedule of Average Annual Percentage Payout of Incurred Claims

The following table shows the average annual percentage payout of incurred losses for the commercial property line of business:

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5
Average annual percentage payout	66.9%	26.2%	4.5%	1.5%	0.1%

The following table shows the average annual percentage payout of incurred losses for the homeowner line of business:

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5
Average annual percentage payout	70.9%	23.0%	4.4%	1.2%	0.3%

The following table shows the average annual percentage payout of incurred losses for the commercial casualty line of business:

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5	6	7	8	9	10
Average annual percentage payout	7.8%	15.0%	18.2%	18.4%	13.3%	9.1%	4.8%	3.9%	2.2%	0.8%

The following table shows the average annual percentage payout of incurred losses for the workers’ compensation line of business:

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5	6	7	8	9	10
Average annual percentage payout	26.4%	26.7%	12.0%	7.0%	3.9%	2.2%	1.3%	1.0%	1.2%	0.8%

The following table shows the average annual percentage payout of incurred losses for the commercial auto line of business. Commercial auto includes both physical damage and liability losses. A majority of the incurred losses paid after year 2 are the result of liability losses.

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5
Average annual percentage payout	41.4%	18.4%	15.5%	12.1%	6.3%

The following table shows the average annual percentage payout of incurred losses for the personal auto line of business. Personal auto includes both physical damage and liability losses. A majority of the incurred losses paid after year 2 are the result of liability losses.

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5
Average annual percentage payout	64.2%	17.4%	9.1%	5.4%	2.4%

The following table shows the average annual percentage payout of incurred losses for the excess and surplus lines insurance segment. Excess and surplus lines consist mostly of commercial casualty and commercial property coverages. A majority of the incurred losses paid after year 2 are the result of commercial casualty losses.

Average annual percentage payout of incurred losses by age, net of reinsurance (unaudited)
Years	1	2	3	4	5	6	7	8	9
Average annual percentage payout	15.3%	14.4%	19.1%	15.5%	11.6%	7.2%	3.3%	1.3%	0.8%