Consolidated Statement of Changes in Equity (Unaudited) - USD ($) $ in Millions	Total	Total	Common Shares	Common Stock and Capital Surplus	Retained Earnings	Accumulated Other Comp. Income Loss
Beginning Balance (shares) at Dec. 31, 2020			86,345,246
Beginning Balance at Dec. 31, 2020		$ 6,789		$ 1,367	$ 4,149	$ 1,273
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 1,640	1,640			1,640
Other comprehensive loss		(1,113)				(1,113)
Dividends		(1,826)			(1,826)
Shares issued:
Exercise of stock options (shares)			1,118,586
Exercise of stock options		55		55
Restricted stock awards (shares)			207,020
Other benefit plans (shares)			60,494
Other benefit plans		7		7
Dividend reinvestment plan (shares)			42,926
Dividend reinvestment plan		5		5
Stock-based compensation expense		11		11
Shares acquired and retired (shares)			(2,769,182)
Shares acquired and retired		(318)		(44)	(274)
Shares exchanged — benefit plans (shares)			(91,926)
Shares exchanged — benefit plans		(10)		(1)	(9)
Forfeitures of restricted stock (shares)			(118,156)
Ending Balance (shares) at Sep. 30, 2021			84,795,008
Ending Balance at Sep. 30, 2021		5,240		1,400	3,680	160
Beginning Balance (shares) at Jun. 30, 2021			84,713,927
Beginning Balance at Jun. 30, 2021		5,601		1,388	4,023	190
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 219	219			219
Other comprehensive loss		(30)				(30)
Dividends		(551)			(551)
Shares issued:
Exercise of stock options (shares)			153,842
Exercise of stock options		6		6
Other benefit plans (shares)			17,029
Other benefit plans		2		2
Dividend reinvestment plan (shares)			6,272
Dividend reinvestment plan		1		1
Stock-based compensation expense		4		4
Shares acquired and retired (shares)			(94,960)
Shares acquired and retired		(12)		(1)	(11)
Shares exchanged — benefit plans (shares)			(562)
Forfeitures of restricted stock (shares)			(540)
Ending Balance (shares) at Sep. 30, 2021			84,795,008
Ending Balance at Sep. 30, 2021		5,240		1,400	3,680	160
Beginning Balance (shares) at Dec. 31, 2021	84,920,965		84,920,965
Beginning Balance at Dec. 31, 2021		5,012		1,415	3,478	119
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 622	622			622
Other comprehensive loss		(721)				(721)
Dividends		(993)			(993)
Shares issued:
Exercise of stock options (shares)			138,498
Exercise of stock options		5		5
Restricted stock awards (shares)			151,080
Other benefit plans (shares)			54,171
Other benefit plans		7		7
Dividend reinvestment plan (shares)			27,518
Dividend reinvestment plan		4		4
Stock-based compensation expense		14		14
Shares acquired and retired (shares)			(80,701)
Shares acquired and retired		(10)		(1)	(9)
Shares exchanged — benefit plans (shares)			(57,195)
Shares exchanged — benefit plans		(8)		(1)	(7)
Forfeitures of restricted stock (shares)			(13,815)
Ending Balance (shares) at Sep. 30, 2022	85,140,521		85,140,521
Ending Balance at Sep. 30, 2022		3,932		1,443	3,091	(602)
Beginning Balance (shares) at Jun. 30, 2022			85,154,263
Beginning Balance at Jun. 30, 2022		4,067		1,436	2,979	(348)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 165	165			165
Other comprehensive loss		(254)				(254)
Dividends		(48)			(48)
Shares issued:
Exercise of stock options (shares)			14,553
Other benefit plans (shares)			19,220
Other benefit plans		2		2
Dividend reinvestment plan (shares)			1,328
Dividend reinvestment plan		1		1
Stock-based compensation expense		4		4
Shares acquired and retired (shares)			(45,500)
Shares acquired and retired		(5)			(5)
Shares exchanged — benefit plans (shares)			(886)
Forfeitures of restricted stock (shares)			(2,457)
Ending Balance (shares) at Sep. 30, 2022	85,140,521		85,140,521
Ending Balance at Sep. 30, 2022		$ 3,932		$ 1,443	$ 3,091	$ (602)