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, 2023			83,635,807
Beginning Balance at Dec. 31, 2023		$ 4,258		$ 1,456	$ 3,121	$ (319)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 242	242			242
Other comprehensive income		4				4
Dividends		(269)			(269)
Shares issued:
Exercise of stock options (shares)			92,851
Exercise of stock options		4		4
Restricted stock awards (shares)			157,681
Other benefit plans (shares)			15,804
Other benefit plans		2		2
Dividend reinvestment plan (shares)			8,253
Dividend reinvestment plan		1		1
Stock-based compensation expense		4		4
Shares acquired and retired (shares)			0
Shares acquired and retired		0		0	0
Shares exchanged — benefit plans (shares)			(47,870)
Shares exchanged — benefit plans		(6)		(1)	(5)
Forfeitures of restricted stock (shares)			(5,172)
Ending Balance (shares) at Mar. 31, 2024			83,857,354
Ending Balance at Mar. 31, 2024		4,240		1,466	3,089	(315)
Beginning Balance (shares) at Dec. 31, 2024	83,978,258		83,978,258
Beginning Balance at Dec. 31, 2024		4,466		1,495	3,211	(240)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 154	154			154
Other comprehensive income		61				61
Dividends		(234)			(234)
Shares issued:
Exercise of stock options (shares)			18,932
Exercise of stock options		1		1
Restricted stock awards (shares)			166,297
Other benefit plans (shares)			15,657
Other benefit plans		2		2
Dividend reinvestment plan (shares)			7,020
Dividend reinvestment plan		1		1
Stock-based compensation expense		4		4
Shares acquired and retired (shares)			(462,398)
Shares acquired and retired		(58)		(9)	(49)
Shares exchanged — benefit plans (shares)			(42,809)
Shares exchanged — benefit plans		(5)		(1)	(4)
Forfeitures of restricted stock (shares)			(12,504)
Ending Balance (shares) at Mar. 31, 2025	83,668,453		83,668,453
Ending Balance at Mar. 31, 2025		$ 4,392		$ 1,493	$ 3,078	$ (179)