Segments of Operations (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Segment Reporting Information [Line Items]
Total premiums earned	$ 985		$ 931	$ 1,931		$ 1,685
Net investment income	404		379	792		740
Other income	90		26	137		47
Revenues before realized gains (losses)	1,542		1,380	2,979		2,572
Realized gains (losses) on securities	(1)		12	18		31
Realized loss on subsidiaries	0		0	(162)		0
Total revenues	1,541		1,392	2,835		2,603
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Net investment income	83		76	162		143
Other income	53	[1]	2	59	[1]	4
Revenues before realized gains (losses)	1,121		1,009	2,152		1,832
Annuity [Member]
Segment Reporting Information [Line Items]
Net investment income	306		289	598		564
Other income	22		19	46		37
Revenues before realized gains (losses)	328		308	644		601
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)	49		48	95		99
Other [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)	44		15	88		40
Specialty Property and transportation [Member]
Segment Reporting Information [Line Items]
Total premiums earned	327		324	640		625
Specialty casualty [Member]
Segment Reporting Information [Line Items]
Total premiums earned	503		467	993		780
Specialty financial [Member]
Segment Reporting Information [Line Items]
Total premiums earned	129		116	249		233
Specialty Other [Member]
Segment Reporting Information [Line Items]
Total premiums earned	$ 26		$ 24	$ 49		$ 47

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