Segments of Operations (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating earnings before income taxes by significant business segment and sub-segment
Realized gains (losses)	$ 44	$ (3)
Operating earnings before income taxes	146	102
Property and Casualty Insurance [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	48	55
Investment and other income, net	55	69
Realized gains (losses)	31
Operating earnings before income taxes	134	124
Annuity and Supplemental Insurance [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Operations	67	54
Realized gains (losses)	13	(3)
Operating earnings before income taxes	80	51
Other Segment [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Operating earnings before income taxes	(68)	(73)
Specialty Property and Transportation [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	27	36
Specialty Casualty [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	4	1
Specialty Financial [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	16	16
Specialty Other [Member]
Operating earnings before income taxes by significant business segment and sub-segment
Property and casualty insurance underwriting income (loss)	$ 1	$ 2