Note 10 - Income Taxes (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			$ 146
Increase (Decrease) in Obligation, Pension Benefits	$ 7	$ (1)	7
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax, Total	5	1	(4)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Total	2		3
Income Taxes Paid, Net, Total	23	$ 34	$ 2
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	438
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	$ 677