Consolidated Statement of Changes in Equity (Unaudited) - 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change for variable interest entities	$ 2	$ 2			$ 2
Beginning Balance, shares at Dec. 31, 2014			87,708,793
Beginning Balance at Dec. 31, 2014	5,054	4,879		$ 1,240	(2)	$ 2,914	$ 727	$ 175
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	240	223				223		17
Other comprehensive income (loss)	(270)	(266)					(266)	(4)
Dividends on Common Stock	(66)	(66)				(66)
Shares issued:
Exercise of stock options, shares			1,157,288
Exercise of stock options	37	37		37
Restricted stock awards, shares			171,130
Restricted stock awards	0	0		0
Other benefit plans, shares			97,817
Other benefit plans	6	6		6
Dividend reinvestment plan, shares			10,359
Dividend reinvestment plan	1	1		1
Stock-based compensation:
Stock-based compensation: Expense	14	14		14
Stock-based compensation: Excess tax benefits	9	9		9
Shares acquired and retired, shares			(1,767,240)
Shares acquired and retired	(113)	(113)		(25)		(88)
Shares exchanged - benefit plans, shares			(33,795)
Shares exchanged - benefit plans	(2)	(2)				(2)
Forfeitures of restricted stock, shares			(17,180)
Forfeitures of restricted stock	0	0		0
Other	(6)							(6)
Ending Balance, shares at Sep. 30, 2015			87,327,172
Ending Balance at Sep. 30, 2015	$ 4,906	4,724		1,282	0	2,981	461	182
Beginning Balance, shares at Dec. 31, 2015	87,474,452		87,474,452
Beginning Balance at Dec. 31, 2015	$ 4,770	4,592		1,301	0	2,987	304	178
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	280	264				264		16
Other comprehensive income (loss)	456	449					449	7
Dividends on Common Stock	(73)	(73)				(73)
Shares issued:
Exercise of stock options, shares			753,095
Exercise of stock options	26	26		26
Restricted stock awards, shares			318,940
Restricted stock awards	0	0		0
Other benefit plans, shares			82,087
Other benefit plans	6	6		6
Dividend reinvestment plan, shares			10,930
Dividend reinvestment plan	1	1		1
Stock-based compensation:
Stock-based compensation: Expense	15	15		15
Stock-based compensation: Excess tax benefits	7	7		7
Shares acquired and retired, shares			(1,796,009)
Shares acquired and retired	(124)	(124)		(27)		(97)
Shares exchanged - benefit plans, shares			(28,059)
Shares exchanged - benefit plans	(2)	(2)				(2)
Forfeitures of restricted stock, shares			(2,785)
Forfeitures of restricted stock	0	0		0
Other	$ (4)							(4)
Ending Balance, shares at Sep. 30, 2016	86,812,651		86,812,651
Ending Balance at Sep. 30, 2016	$ 5,358	$ 5,161		$ 1,329	$ 0	$ 3,079	$ 753	$ 197