Note 9 - Long-term Debt Components (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Revolving Credit Facility [Member]
Long-term debt, interest rate	1.90%
Long-term debt maturity	2020
Long-term debt	$ 110	$ 110
Unsecured Term Note Payable [Member]
Long-term debt, interest rate	3.00%
Long-term debt maturity	2018
Long-term debt	$ 10	10
Long-term debt	120	120
Long-term debt, noncurrent	$ 120	$ 120