Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment Information

Segment information is summarized in the following table:

(Dollars in millions)	Years ended December 31,
	2017			2016			2015
Revenues:
Commercial lines insurance
Commercial casualty	$	1,072		$	1,050		$	1,010
Commercial property	903			867			815
Commercial auto	634			594			561
Workers' compensation	335			354			367
Other commercial	221			224			243
Commercial lines insurance premiums	3,165			3,089			2,996
Fee revenues	5			5			4
Total commercial lines insurance	3,170			3,094			3,000
Personal lines insurance
Personal auto	582			543			506
Homeowner	518			486			463
Other personal	141			132			128
Personal lines insurance premiums	1,241			1,161			1,097
Fee revenues	5			4			3
Total personal lines insurance	1,246			1,165			1,100
Excess and surplus lines insurance	209			183			168
Fee revenues	1			1			1
Total excess and surplus lines insurance	210			184			169
Life insurance premiums	232			228			209
Fee revenues	5			5			5
Total life insurance	237			233			214
Investments
Investment income, net of expenses	609			595			572
Realized investment gains, net	148			124			70
Total investment revenue	757			719			642
Other
Cincinnati Re insurance premiums	107			49			10
Other	5			5			7
Total other revenue	112			54			17
Total revenues	$	5,732		$	5,449		$	5,142
Income (loss) before income taxes:
Insurance underwriting results
Commercial lines insurance	$	119		$	184		$	345
Personal lines insurance	(32		)	(12		)	(12		)
Excess and surplus lines insurance	61			62			51
Life insurance	(1		)	1			(2		)
Investments	664			629			556
Other	(81		)	(52		)	(57		)
Total income before income taxes	$	730		$	812		$	881
	December 31,			December 31,
Identifiable assets:	2017			2016
Property casualty insurance	$	2,863		$	2,967
Life insurance	1,409			1,366
Investments	17,112			15,569
Other	459			484
Total	$	21,843		$	20,386