Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011		Jun. 30, 2012	Jun. 30, 2011
Revenues [Abstract]
Premiums Earned	$ 2,983	$ 2,913		$ 5,934	$ 5,767
Investment Income	390	416		791	820
Other Revenues	3	2		5	4
Realized Investment Gains (Losses), Net [Abstract]
Total Other-Than-Temporary Impairment Losses on Investments	(30)	(14)		(35)	(16)
Other-Than-Temporary Impairment Losses on Investments Recognized in Other Comprehensive Income	(1)			(2)
Other Realized Investment Gains, Net	78	83		140	245
Total Realized Investment Gains, Net	47	69		103	229
Total Revenues	3,423	3,400		6,833	6,820
Losses and Expenses [Abstract]
Losses and Loss Expenses	1,860	1,847		3,567	3,612
Amortization of Deferred Policy Acquisition Costs	607	583	[1]	1,183	1,123	[1]
Other Insurance Operating Costs and Expenses	351	337	[1]	717	679	[1]
Investment Expenses	10	12		21	23
Other Expenses	3	3		6	5
Corporate Expenses	65	72		133	147
Total Losses and Expenses	2,896	2,854		5,627	5,589
Income Before Federal and Foreign Income Tax	527	546		1,206	1,231
Federal and Foreign Income Tax	123	127		296	303
Net Income	$ 404	$ 419		$ 910	$ 928
Net Income Per Share [Abstract]
Basic	$ 1.49	$ 1.43		$ 3.33	$ 3.14
Diluted	$ 1.48	$ 1.42		$ 3.31	$ 3.12
Dividends Declared Per Share	$ 0.41	$ 0.39		$ 0.82	$ 0.78

[1] As Adjusted