Note 10 - Income Taxes - Activity in Uncertain Tax Positions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Balance at beginning of period	$ 14	$ 15	$ 15
Statute expirations	(14)	(1)	0
Balance at end of period	$ 0	$ 14	$ 15