Note 8 - Stock-based Compensation - Stock-based Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Stock-based compensation expense, gross	$ 5	$ 5	$ 17	$ 14
Income tax benefit at our statutory rate associated with share-based compensation	(1)	(1)	(4)	(4)
Stock-based compensation expense, net	$ 4	$ 4	$ 13	$ 10