Segments of Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Total premiums earned	$ 754	$ 687
Net investment income	361	326
Other income	21	22
Revenues before realized gains (losses)	1,192	1,091
Realized gains on securities	19	57
Total revenues	1,211	1,148
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Net investment income	67	66
Other income	2	3
Revenues before realized gains (losses)	823	756
Annuity [Member]
Segment Reporting Information [Line Items]
Net investment income	275	248
Other income	18	14
Revenues before realized gains (losses)	293	262
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)	51	50
Other [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)	25	23
Specialty Property and transportation [Member]
Segment Reporting Information [Line Items]
Total premiums earned	301	293
Specialty casualty [Member]
Segment Reporting Information [Line Items]
Total premiums earned	313	259
Specialty financial [Member]
Segment Reporting Information [Line Items]
Total premiums earned	117	116
Specialty Other [Member]
Segment Reporting Information [Line Items]
Total premiums earned	$ 23	$ 19