Condensed Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
REVENUES
Earned premiums	$ 931	$ 839
Investment income, net of expenses	128	131
Total realized investment gains, net	41	13
Fee revenues	1	1
Other revenues	2	2
Total revenues	1,103	986
BENEFITS AND EXPENSES
Insurance losses and policyholder benefits	568	582
Underwriting, acquisition and insurance expenses	300	274
Interest expense	13	14
Other operating expenses	5	4
Total benefits and expenses	886	874
INCOME BEFORE INCOME TAXES	217	112
PROVISION FOR INCOME TAXES
Current	54	20
Deferred	9	6
Total provision for income taxes	63	26
NET INCOME	$ 154	$ 86
PER COMMON SHARE
Net income-basic (in USD per share)	$ 0.95	$ 0.53
Net income-diluted (in USD per share)	$ 0.94	$ 0.53