Note 9 - Leases (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Lease, Cost	$ 13	$ 11
Short-term Lease, Cost	1	$ 3
Operating Lease, Payments	14
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 14
Operating Lease, Weighted Average Remaining Lease Term (Year)	10 years 9 months
Operating Lease, Weighted Average Discount Rate, Percent	6.76%
Minimum [Member]
Lessee, Operating Lease, Remaining Lease Term (Year)	1 year
Lessee, Lease, Renewal Term (Year)	1 year
Maximum [Member]
Lessee, Operating Lease, Remaining Lease Term (Year)	99 years
Lessee, Lease, Renewal Term (Year)	20 years