Note 11 - Retirement Plans - Summary of Funded Status and Amounts Recognized on Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Projected benefit obligation at beginning of year	$ 140	$ 151
Interest cost	4	4	$ 4
Actuarial (gain) loss	(38)	(11)
Benefits paid	(4)	(4)
Projected benefit obligation at end of year	102	140	151
Fair value of pension plan assets at beginning of year	119	108
Actual return on plan assets	(14)	12
Company contributions	4	4
Benefits paid	(5)	(5)
Fair value of pension plan assets at end of year	104	119	$ 108
Funded status of pension plan	2	(21)
Accrued benefit cost	21	15
Accumulated other comprehensive loss	(19)	(36)
Net asset (liability) recognized	$ 2	$ (21)