Note 5 - Retirement Plans - Components of Net Periodic Pension and OPEB Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net periodic pension (benefit)/cost	$ (2)	$ (1)
Pension Plan [Member]
Service cost	13	13
Interest cost	46	46
Expected return on plan assets	(63)	(62)
Amortization of actuarial loss	$ 2	$ 2