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, 2021			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 (in 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
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 acquired and retired		0
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
Ending Balance at Jun. 30, 2022		4,067		1,436	2,979	(348)
Beginning Balance (shares) at Dec. 31, 2022	85,204,006		85,204,006
Beginning Balance at Dec. 31, 2022		4,052		1,453	3,142	(543)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 412	412			412
Other comprehensive loss		32				32
Dividends		(448)			(448)
Shares issued:
Exercise of stock options (shares)			77,401
Exercise of stock options		3		3
Restricted stock awards (shares)			165,513
Other benefit plans (shares)			46,287
Other benefit plans		6		6
Dividend reinvestment plan (shares)			12,463
Dividend reinvestment plan		2		2
Stock-based compensation expense		9		9
Shares acquired and retired (in shares)			574,720
Shares acquired and retired		(67)		(10)	(57)
Shares exchanged — benefit plans (shares)			(56,436)
Shares exchanged — benefit plans		(8)		(1)	(7)
Forfeitures of restricted stock (shares)			(15,986)
Ending Balance (shares) at Jun. 30, 2023	84,858,528		84,858,528
Ending Balance at Jun. 30, 2023		3,993		1,462	3,042	(511)
Beginning Balance (shares) at Mar. 31, 2023			85,171,658
Beginning Balance at Mar. 31, 2023		3,941		1,459	2,933	(451)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 200	200			200
Other comprehensive loss		(60)				(60)
Dividends		(54)			(54)
Shares issued:
Exercise of stock options (shares)			13,062
Restricted stock awards (shares)			18,344
Other benefit plans (shares)			33,988
Other benefit plans		4		4
Dividend reinvestment plan (shares)			1,552
Dividend reinvestment plan		1		1
Stock-based compensation expense		4		4
Shares acquired and retired (in shares)			374,958
Shares acquired and retired		(43)		(6)	(37)
Shares exchanged — benefit plans (shares)			(1,054)
Forfeitures of restricted stock (shares)			(4,064)
Ending Balance (shares) at Jun. 30, 2023	84,858,528		84,858,528
Ending Balance at Jun. 30, 2023		$ 3,993		$ 1,462	$ 3,042	$ (511)