Note 9 - Stock-based Compensation - Stock-based Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock-based compensation expense, gross	$ 5	$ 2	$ 10	$ 6
Forfeitures	0	0	0	(1)
Income tax benefit at our statutory rate associated with share-based compensation	(1)	(1)	(3)	(1)
Stock-based compensation expense, net	$ 4	$ 1	$ 7	$ 4