Note 5 - Retirement Plans - Components of Net Periodic Pension and OPEB Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net periodic pension (benefit)/cost	$ 0	$ 1	$ (3)	$ (2)
Pension Plan [Member]
Service cost	12	13	39	38
Interest cost	47	48	139	140
Expected return on plan assets	(63)	(62)	(189)	(186)
Amortization of actuarial loss	$ 4	$ 2	$ 8	$ 6