Consolidated Statement of Changes in Equity (USD $) In Millions, except Share data, unless otherwise specified	Total USD ($)	Common Shares	Common Stock and Capital Surplus USD ($)	Retained Earnings Approp. USD ($)	Retained Earnings Unapprop. USD ($)	Accumulated Other Comprehensive Inc. (Loss) USD ($)	Total USD ($)	Noncontrolling Interests USD ($)
Beginning Balance at Dec. 31, 2009	$ 3,761		$ 1,344	$ 0	$ 2,115	$ 164	$ 3,623	$ 138
Cumulative effect of accounting change for deferred policy acquisition costs at Dec. 31, 2009	(158)				(159)	1	(158)
Beginning Balance, shares at Dec. 31, 2009		113,386,343
Beginning Balance, as adjusted at Dec. 31, 2009	3,919		1,344		2,274	163	3,781	138
Beginning Balance, as adjusted, shares at Dec. 31, 2009		113,386,343
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change for consolidation of variable interest entities	261			261	4	(4)	261
Net earnings	426				482		482	(56)
Other comprehensive income	338					336	336	2
Allocation of losses of managed investment entities	0			(64)			(64)	64
Dividends on Common Stock	(63)				(63)		(63)
Shares issued:
Exercise of stock options, shares		1,547,526
Exercise of stock options	31		31				31
Other benefit plans, shares		479,514
Other benefit plans	6		6				6
Dividend reinvestment plan, shares		17,028
Stock-based compensation expense	12		12				12
Shares acquired and retired, shares		(10,261,045)
Shares acquired and retired	(292)		(122)		(170)		(292)
Shares exchanged - benefit plans, shares		(1,000)
Other	1					(1)	(1)	2
Ending Balance at Dec. 31, 2010	4,481		1,271	197	2,368	495	4,331	150
Ending Balance, shares at Dec. 31, 2010		105,168,366
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	319				342		342	(23)
Other comprehensive income	91					85	85	6
Allocation of losses of managed investment entities	0			(24)			(24)	24
Dividends on Common Stock	(69)				(69)		(69)
Shares issued:
Exercise of stock options, shares		1,576,664
Exercise of stock options	38		38				38
Other benefit plans, shares		387,746
Other benefit plans	9		9				9
Dividend reinvestment plan, shares		15,763
Dividend reinvestment plan	1		1				1
Stock-based compensation expense	14		14				14
Shares acquired and retired, shares		(9,281,386)
Shares acquired and retired	(315)		(113)		(202)		(315)
Shares exchanged - benefit plans, shares		(20,751)
Shares exchanged - benefit plans	(1)		(1)				(1)
Other	(11)							(11)
Ending Balance at Dec. 31, 2011	4,557		1,219	173	2,439	580	4,411	146
Ending Balance, shares at Dec. 31, 2011	97,846,402	97,846,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	402				488		488	(86)
Other comprehensive income	260					252	252	8
Allocation of losses of managed investment entities	0			(98)			(98)	98
Dividends on Common Stock	(91)				(91)		(91)
Shares issued:
Exercise of stock options, shares	1,702,782	1,702,782
Exercise of stock options	45		45				45
Other benefit plans, shares		308,352
Other benefit plans	7		7				7
Dividend reinvestment plan, shares		21,484
Dividend reinvestment plan	1		1				1
Stock-based compensation expense	18		18				18
Shares acquired and retired, shares		(10,864,184)
Shares acquired and retired	(415)		(137)		(278)		(415)
Shares exchanged - benefit plans, shares		(35,533)
Shares exchanged - benefit plans	(1)		(1)				(1)
Other	(35)				(38)	(1)	(39)	4
Ending Balance at Dec. 31, 2012	$ 4,748		$ 1,152	$ 75	$ 2,520	$ 831	$ 4,578	$ 170
Ending Balance, shares at Dec. 31, 2012	88,979,303	88,979,303