Recent Accounting Pronouncements (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 International Segment [Member]	Jun. 30, 2011 International Segment [Member]	Jun. 30, 2012 International Segment [Member]	Jun. 30, 2011 International Segment [Member]	Jun. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member]	Jun. 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]	Jun. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member] International Segment [Member]	Jun. 30, 2011 Accounting Standards Update 2010-26 [Member] Scenario, Previously Reported [Member] International Segment [Member]	Jun. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member]	Jun. 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]	Jun. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member] International Segment [Member]	Jun. 30, 2011 Accounting Standards Update 2010-26 [Member] Restatement Adjustment [Member] International Segment [Member]
Condensed Consolidated Statement of Income
Revenue, excluding other revenues		$ 5,436		$ 10,813						$ 5,436	$ 10,813				$ 0	$ 0
Other revenues	90	71	50	105						73	109				(2)	(4)
Total revenues	7,457	5,507	14,245	10,918						5,509	10,922				(2)	(4)
Benefits and expenses, excluding other operating expenses		3,418		6,749						3,418	6,749				0	0
Other operating expenses	1,833	1,497	3,674	2,998						1,475	2,957				22	41
Total benefits and expenses	6,869	4,915	13,105	9,747						4,893	9,706				22	41
Income before Income Taxes	588	592	1,140	1,171						616	1,216				(24)	(45)
Current income taxes	211	138	346	160						138	160				0	0
Deferred income taxes	(3)	63	43	206						70	218				(7)	(12)
Total taxes	208	201	389	366						208	378				(7)	(12)
Net Income	380	391	751	805						408	838				(17)	(33)
Less: Net Income Attributable to Noncontrolling Interest	0	0	0	1						0	1				0	0
Shareholders' net income	380	391	751	804						408	837				(17)	(33)	(67)
Earnings per share:
Basic	$ 1.33	$ 1.46	$ 2.63	$ 2.98						$ 1.52	$ 3.11				$ (0.06)	$ (0.13)
Diluted	$ 1.31	$ 1.43	$ 2.59	$ 2.94						$ 1.50	$ 3.06				$ (0.07)	$ (0.12)
Balance sheet
Deferred policy acquisition costs	900		900		817							1,312					(495)
Deferred income taxes, net	499		499		803							632					171
Other assets, including other intangibles	2,472		2,472		1,750							1,776					(26)
All other assets					47,327							47,327					0
Total assets	53,553		53,553		50,697							51,047					(350)
Net translation foreign currencies	(5)		(5)		3							(3)					6
Retained earnings	11,501		11,501		10,787							11,143					(356)
Other Shareholders Equity					(2,796)							(2,796)					0
Total shareholders' equity	9,022		9,022		7,994							8,344					(350)	(289)
Statement of Cash Flows
Net Income	380	391	751	805						408	838				(17)	(33)
Deferred income taxes			43	206							218					(12)
Deferred policy acquisition costs			(72)	(75)							(116)					41
Other assets			(69)	(40)							(44)					4
Segment information: International
Premiums and fees, Mail order pharmacy revenues and Other revenues	7,178	5,206	13,665	10,312		904	740	1,779	1,444				742	1,448					(2)	(4)
Segment earnings	$ 383	$ 380	$ 742	$ 776		$ 65	$ 57	$ 145	$ 118				$ 74	$ 151					$ (17)	$ (33)