Note 10 - Income Taxes - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statutory federal rate applied to income before income tax expense	$ 53	$ 60	$ 68
Current year permanent items	13	3	2
State and local taxes, net of federal tax benefit	13	14	8
Change in valuation allowance	(2)	0	(2)
Reserve for uncertain tax positions	0	0	1
Rate change due to enactment of tax reform	0	0	(146)
Other items, net	(1)	0	0
Income tax expense (benefit) as recorded	$ 76	$ 77	$ (69)
Effective income tax rate	30.00%	27.00%	(36.00%)