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	$ 1,421	1,421			1,421
Other comprehensive loss		(1,083)				(1,083)
Dividends		(1,275)			(1,275)
Shares issued:
Exercise of stock options (shares)			964,744
Exercise of stock options		49		49
Restricted stock awards (shares)			207,020
Other benefit plans (shares)			43,465
Other benefit plans		5		5
Dividend reinvestment plan (shares)			36,654
Dividend reinvestment plan		4		4
Stock-based compensation expense		7		7
Shares acquired and retired (shares)			(2,674,222)
Shares acquired and retired		(306)		(43)	(263)
Shares exchanged — benefit plans (shares)			(91,364)
Shares exchanged — benefit plans		(10)		(1)	(9)
Forfeitures of restricted stock (shares)			(117,616)
Ending Balance (shares) at Jun. 30, 2021			84,713,927
Ending Balance at Jun. 30, 2021		5,601		1,388	4,023	190
Beginning Balance (shares) at Mar. 31, 2021			85,126,062
Beginning Balance at Mar. 31, 2021		6,685		1,364	4,354	967
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 1,002	1,002			1,002
Other comprehensive loss		(777)				(777)
Dividends		(1,232)			(1,232)
Shares issued:
Exercise of stock options (shares)			561,732
Exercise of stock options		30		30
Other benefit plans (shares)			27,833
Other benefit plans		3		3
Dividend reinvestment plan (shares)			34,348
Dividend reinvestment plan		4		4
Stock-based compensation expense		2		2
Shares acquired and retired (shares)			(916,520)
Shares acquired and retired		(114)		(15)	(99)
Shares exchanged — benefit plans (shares)			(14,380)
Shares exchanged — benefit plans		(2)			(2)
Forfeitures of restricted stock (shares)			(105,148)
Ending Balance (shares) at Jun. 30, 2021			84,713,927
Ending Balance at Jun. 30, 2021		5,601		1,388	4,023	190
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	$ 457	457			457
Other comprehensive loss		(467)				(467)
Dividends		(945)			(945)
Shares issued:
Exercise of stock options (shares)			123,945
Exercise of stock options		5		5
Restricted stock awards (shares)			151,080
Other benefit plans (shares)			34,951
Other benefit plans		5		5
Dividend reinvestment plan (shares)			26,190
Dividend reinvestment plan		3		3
Stock-based compensation expense		10		10
Shares acquired and retired (shares)			(35,201)
Shares acquired and retired		(5)		(1)	(4)
Shares exchanged — benefit plans (shares)			(56,309)
Shares exchanged — benefit plans		(8)		(1)	(7)
Forfeitures of restricted stock (shares)			(11,358)
Ending Balance (shares) at Jun. 30, 2022	85,154,263		85,154,263
Ending Balance at Jun. 30, 2022		4,067		1,436	2,979	(348)
Beginning Balance (shares) at Mar. 31, 2022			85,102,829
Beginning Balance at Mar. 31, 2022		4,835		1,425	3,541	(131)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 167	167			167
Other comprehensive loss		(217)				(217)
Dividends		(728)			(728)
Shares issued:
Exercise of stock options (shares)			18,541
Exercise of stock options		1		1
Other benefit plans (shares)			24,344
Other benefit plans		4		4
Dividend reinvestment plan (shares)			19,908
Dividend reinvestment plan		2		2
Stock-based compensation expense		4		4
Shares exchanged — benefit plans (shares)			(8,400)
Shares exchanged — benefit plans		(1)			(1)
Forfeitures of restricted stock (shares)			(2,959)
Ending Balance (shares) at Jun. 30, 2022	85,154,263		85,154,263
Ending Balance at Jun. 30, 2022		$ 4,067		$ 1,436	$ 2,979	$ (348)