Note 3 - Available-for-Sale Investments (Details) - Securities in a Continuous Unrealized Loss Position $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Securities in a Continuous Unrealized Loss Position [Abstract]
Number of securities in a loss position	21	21
12 months or greater, fair value	$ 33	$ 37
12 months or greater, unrealized losses	(4)	(4)
Total, fair value	33	37
Total, unrealized losses	$ (4)	$ (4)