Note 7 - Stock-based Compensation - Stock-based Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Stock-based compensation expense, gross	$ 6	$ 7	$ 12	$ 9
Income tax benefit at our statutory rate associated with stock-based compensation	(2)	(2)	(3)	(2)
Stock-based compensation expense, net	$ 4	$ 5	$ 9	$ 7