Segments of Operations (Details 1) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Operating earnings before income taxes by significant business segment and sub-segment
Realized gains (losses)	$ 8	$ 35	$ 24	$ 50
Operating earnings before income taxes	155	208	319	513
Specialty Property and Transportation [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	5	41	38	81
Specialty Casualty [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	20	(13)	43	29
Specialty Financial [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	23	36	46	91
Specialty Other [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	8	4	14	13
Other Lines [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)			(50)	(12)
Property and Casualty Insurance [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	56	68	91	202
Investment and other income, net	66	67	204	229
Realized gains (losses)	15	46	47	69
Operating earnings before income taxes	137	181	342	500
Annuity and Supplemental Insurance [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Operations	49	58	157	148
Realized gains (losses)	(8)	(11)	(24)	(19)
Operating earnings before income taxes	41	47	133	129
Other Segment [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Operating earnings before income taxes	$ (23)	$ (20)	$ (156)	$ (116)