Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Total	Common Shares	Common Stock and Capital Surplus	Retained Earnings Approp.	Retained Earnings Unapprop.	Accumulated Other Comprehensive Inc. (Loss)	Noncontrolling Interests
Beginning Balance, shares at Dec. 31, 2012			88,979,303
Beginning Balance at Dec. 31, 2012	$ 4,748	$ 4,578		$ 1,152	$ 75	$ 2,520	$ 831	$ 170
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	453	471				471		(18)
Other comprehensive income (loss)	(277)	(271)					(271)	(6)
Allocation of losses of managed investment entities	0	(26)			(26)			26
Dividends on Common Stock	(161)	(161)				(161)
Shares issued:
Exercise of stock options, shares			1,625,023
Exercise of stock options	53	53		53
Other benefit plans, shares			388,043
Other benefit plans	7	7		7
Dividend reinvestment plan, shares			28,147
Dividend reinvestment plan	2	2		2
Stock-based compensation expense	19	19		19
Shares acquired and retired, shares			(1,448,156)
Shares acquired and retired	(70)	(70)		(19)		(51)
Shares exchanged - benefit plans, shares			(58,974)
Shares exchanged - benefit plans	(3)	(3)		(1)		(2)
Other	(2)					0		(2)
Ending Balance, shares at Dec. 31, 2013			89,513,386
Ending Balance at Dec. 31, 2013	4,769	4,599		1,213	49	2,777	560	170
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	406	452				452		(46)
Other comprehensive income (loss)	170	167					167	3
Allocation of losses of managed investment entities	0	(51)			(51)			51
Dividends on Common Stock	(169)	(169)				(169)
Shares issued:
Exercise of stock options, shares			1,262,313
Exercise of stock options	45	45		45
Other benefit plans, shares			242,669
Other benefit plans	8	8		8
Dividend reinvestment plan, shares			27,238
Dividend reinvestment plan	2	2		2
Stock-based compensation expense	19	19		19
Shares acquired and retired, shares			(3,303,639)
Shares acquired and retired	(191)	(191)		(46)		(145)
Shares exchanged - benefit plans, shares			(33,174)
Shares exchanged - benefit plans	(2)	(2)		(1)		(1)
Other	$ (3)	0				0	0	(3)
Ending Balance, shares at Dec. 31, 2014	87,708,793		87,708,793
Ending Balance at Dec. 31, 2014	$ 5,054	4,879		1,240	(2)	2,914	727	175
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change for variable interest entities	2	2			2
Net earnings	370	352				352		18
Other comprehensive income (loss)	(431)	(423)					(423)	(8)
Dividends on Common Stock	$ (178)	(178)				(178)
Shares issued:
Exercise of stock options, shares	1,475,202		1,475,202
Exercise of stock options	$ 59	59		59
Other benefit plans, shares			282,811
Other benefit plans	7	7		7
Dividend reinvestment plan, shares			26,167
Dividend reinvestment plan	2	2		2
Stock-based compensation expense	21	21		21
Shares acquired and retired, shares			(1,955,186)
Shares acquired and retired	(126)	(126)		(27)		(99)
Shares exchanged - benefit plans, shares			(45,765)
Shares exchanged - benefit plans	(3)	(3)		(1)		(2)
Forfeitures of restricted stock, shares			(17,570)
Forfeitures of restricted stock	0	0		0
Other	$ (7)							(7)
Ending Balance, shares at Dec. 31, 2015	87,474,452		87,474,452
Ending Balance at Dec. 31, 2015	$ 4,770	$ 4,592		$ 1,301	$ 0	$ 2,987	$ 304	$ 178