Segments of Operations (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating earnings before income taxes by significant business segment and sub-segment
Operating earnings before income taxes	$ 136	$ 60	$ 282	$ 162
Property and Casualty Insurance [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	45	(21)	93	34
Investment and other income, net	61	71	116	140
Realized gains (losses)	13	32	44	32
Operating earnings before income taxes	119	82	253	206
Annuity and Supplemental Insurance [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Operations	76	56	143	110
Realized gains (losses)	2	(13)	15	(16)
Operating earnings before income taxes	78	43	158	94
Other Segment [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Operating earnings before income taxes	(61)	(65)	(129)	(138)
Specialty Property and Transportation [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	6	(3)	33	33
Specialty Casualty [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	33	17	37	18
Specialty Financial [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	11	12	27	28
Specialty Other [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	2	3	3	5
Other Lines [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	$ (7)	$ (50)	$ (7)	$ (50)