Note 5 - Retirement Plans - Components of Net Periodic Pension and OPEB Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net periodic pension cost	$ 5	$ 24	$ 11	$ 49
Pension Plan [Member]
Service cost	26	30	52	60
Interest cost	31	27	62	53
Expected return on plan assets	(73)	(68)	(146)	(135)
Amortization of actuarial loss	$ 21	$ 35	$ 43	$ 71