Note 10 - Income Taxes (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Increase (Decrease) in Obligation, Pension Benefits	$ 10	$ 7	$ (1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax, Total	(8)	(5)	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Total	2	2
Income Taxes Paid, Net, Total	70	$ 23	$ 34
Unrecognized Tax Benefits, Ending Balance	15
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	1
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	204
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	$ 567