Note 9 - Employee Retirement Plans - Net Periodic Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pension Plan [Member]
Service cost	$ 25	$ 25	$ 73	$ 75
Interest cost	46	45	138	133
Expected return on plan assets	(48)	(46)	(144)	(138)
Amortization of prior service cost (credit)	1	2	4	5
Recognition of actuarial (gain) loss	(31)	12	(31)	(16)
Special termination benefit charge	3		6	5
Total pension and postretirement benefit (income) expense	(4)	38	46	64
Other Postretirement Benefits Plan [Member]
Service cost		1	2	4
Interest cost	4	6	14	17
Amortization of actuarial net gain	(6)	(6)	(18)	(17)
Amortization of prior service cost (credit)	(1)	(2)	(5)	(4)
Total pension and postretirement benefit (income) expense	$ (3)	$ (1)	$ (7)	$ 0