Consolidated Statement of Income (Loss) (Unaudited) (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
Premiums	$ 5,529	$ 5,503	$ 11,052	$ 10,874
Net investment income	738	758	1,478	1,537
Fee income	59	74	141	148
Net realized investment gains	4	19	14	39
Other revenues	29	34	66	68
Total revenues	6,359	6,388	12,751	12,666
Claims and expenses
Claims and claim adjustment expenses	3,786	5,141	7,150	8,523
Amortization of deferred acquisition costs	976	970	1,947	1,918
General and administrative expenses	893	907	1,777	1,790
Interest expense	96	97	192	193
Total claims and expenses	5,751	7,115	11,066	12,424
Income (loss) before income taxes	608	(727)	1,685	242
Income tax expense (benefit)	109	(363)	380	(233)
Net income (loss)	499	(364)	1,305	475
Net income (loss) per share
Net income (loss) per share, basic	$ 1.27	$ (0.88)	$ 3.32	$ 1.11
Net income (loss) per share, diluted	$ 1.26	$ (0.88)	$ 3.29	$ 1.10
Weighted average number of common shares outstanding
Weighted average number of common shares outstanding, basic	388.0	418.6	390.0	423.3
Weighted average number of common shares outstanding, diluted	391.6	418.6	393.5	429.1
Other-than-temporary impairment losses:
Other-than-temporary impairment losses, total gains	11	5	11	7
Other-than-temporary impairment losses, non-credit component of impairments recognized in accumulated other comprehensive income	(15)	(9)	(19)	(15)
Other-than-temporary impairment losses	(4)	(4)	(8)	(8)
Other net realized investment gains	8	23	22	47
Net realized investment gains	$ 4	$ 19	$ 14	$ 39