Note 9 - Employee Retirement Plans - Net Periodic Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension Plan [Member]
Service cost	$ 25	$ 27	$ 48	$ 50
Interest cost	46	43	92	88
Expected return on plan assets	(48)	(46)	(96)	(92)
Amortization of prior service cost (credit)	2	1	3	3
Special termination benefit charge	3	5	3	5
Total pension and postretirement benefit expense (income)	28	30	50	54
Other Postretirement Benefits Plan [Member]
Service cost	1	2	2	3
Interest cost	5	5	10	11
Amortization of actuarial net gain	(7)	(6)	(12)	(11)
Amortization of prior service cost (credit)	(2)	(1)	(4)	(2)
Total pension and postretirement benefit expense (income)	$ (3)	$ 0	$ (4)	$ 1