Note 11 - Retirement Plans - Summary of Funded Status and Amounts Recognized on Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Projected benefit obligation at beginning of year	$ 151	$ 135
Interest cost	4	4	$ 5
Actuarial (gain) loss	(11)	16
Benefits paid	(4)	(4)
Projected benefit obligation at end of year	140	151	135
Fair value of pension plan assets at beginning of year	108	97
Actual return on plan assets	12	12
Company contributions	3	3
Benefits paid	(4)	(4)
Fair value of pension plan assets at end of year	119	108	$ 97
Funded status of pension plan	(21)	(43)
Accrued benefit cost	15	10
Accumulated other comprehensive loss	(36)	(53)
Net liability recognized	$ (21)	$ (43)