Segments of Operations (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Segment Reporting Information [Line Items]
Total premiums earned	$ 1,173		$ 1,132	$ 3,104		$ 2,817
Net investment income	425		377	1,217		1,117
Other income	40		28	177		75
Revenues before realized gains (losses)	1,695		1,568	4,674		4,140
Realized gains (losses) on securities	(16)		13	2		44
Realized gain (loss) on subsidiaries	5		0	(157)		0
Total revenues	1,684		1,581	4,519		4,184
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Net investment income	83		76	245		219
Other income	2	[1]	4	61	[1]	8
Revenues before realized gains (losses)	1,258		1,212	3,410		3,044
Annuity [Member]
Segment Reporting Information [Line Items]
Net investment income	317		287	915		851
Other income	22		20	68		57
Revenues before realized gains (losses)	339		307	983		908
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)	49		48	144		147
Other [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)	49		1	137		41
Specialty Property and transportation [Member]
Segment Reporting Information [Line Items]
Total premiums earned	517		504	1,157		1,129
Specialty casualty [Member]
Segment Reporting Information [Line Items]
Total premiums earned	503		486	1,496		1,266
Specialty financial [Member]
Segment Reporting Information [Line Items]
Total premiums earned	131		115	380		348
Specialty Other [Member]
Segment Reporting Information [Line Items]
Total premiums earned	$ 22		$ 27	$ 71		$ 74

[1] Includes pretax income of $51 million (before noncontrolling interest) from the sale of the Le Pavillon Hotel in the second quarter of 2015.