Recent Accounting Pronouncements (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 International [Member]	Sep. 30, 2011 International [Member]	Sep. 30, 2012 International [Member]	Sep. 30, 2011 International [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member]	Dec. 31, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member] International [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member] International [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member]	Dec. 31, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member]	Dec. 31, 2010 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member] International [Member]	Sep. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member] International [Member]
Condensed Consolidated Statement of Income
Revenue, excluding other revenues		$ 5,426		$ 16,239						$ 5,426	$ 16,239				$ 0	$ 0
Other revenues	26	184	76	289						187	296				(3)	(7)
Total revenues	7,358	5,610	21,603	16,528						5,613	16,535				(3)	(7)
Benefits and expenses, excluding other operating expenses		3,819		10,568						3,819	10,568				0	0
Other operating expenses	1,897	1,518	5,571	4,516						1,497	4,454				21	62
Total benefits and expenses	6,640	5,337	19,745	15,084						5,316	15,022				21	62
Income before Income Taxes	718	273	1,858	1,444						297	1,513				(24)	(69)
Current income taxes	228	114	574	274						114	274				0	0
Deferred income taxes	24	(24)	67	182						(17)	201				(7)	(19)
Total taxes	252	90	641	456						97	475				(7)	(19)
Net Income	466	183	1,217	988						200	1,038				(17)	(50)
Less: Net Income Attributable to Noncontrolling Interest	0	0	0	1						0	1				0	0
Shareholders' net income	466	183	1,217	987						200	1,037				(17)	(50)	(67)
Earnings per share:
Basic	$ 1.64	$ 0.68	$ 4.27	$ 3.67						$ 0.74	$ 3.85				$ (0.06)	$ (0.18)
Diluted	$ 1.61	$ 0.67	$ 4.20	$ 3.62						$ 0.74	$ 3.80				$ (0.07)	$ (0.18)
Balance sheet
Deferred policy acquisition costs	1,022		1,022		817							1,312					(495)
Deferred income taxes, net	407		407		803							632					171
Other assets, including other intangibles	2,229		2,229		1,750							1,776					(26)
All other assets					47,327							47,327					0
Total assets	53,531		53,531		50,697							51,047					(350)
Net translation foreign currencies	26		26		3							(3)					6
Retained earnings	11,962		11,962		10,787							11,143					(356)
Other Shareholders Equity					(2,796)							(2,796)					0
Total shareholders' equity	9,530		9,530		7,994							8,344					(350)	(289)
Statement of Cash Flows
Net Income	466	183	1,217	988						200	1,038				(17)	(50)
Deferred income taxes			67	182							201					(19)
Deferred policy acquisition costs			(106)	(106)							(168)					62
Other assets			166	(292)							(299)					7
Segment information: International
Premiums and fees, Mail order pharmacy revenues and Other revenues	7,064	5,300	20,729	15,612		938	768	2,717	2,212				771	2,219					(3)	(7)
Segment earnings	$ 459	$ 174	$ 1,201	$ 950		$ 70	$ 62	$ 215	$ 180				$ 79	$ 230					$ (17)	$ (50)