Note 6 - Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Balance at January 1	$ 253	$ 10
Additions based on tax positions related to the current year	10
Additions for tax positions of prior years	4	245
Reductions for tax positions of prior years	(18)	(1)
Settlements and lapse of statute of limitations	(6)	(1)
Balance at December 31	$ 243	$ 253