Note 8 - Stockholders' Equity - Summary of Share Repurchase Activity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Number of shares acquired on the open market (in shares)	0	957,869			0	4,088,490
Average price per share (in dollars per share)	$ 0	$ 13.59			$ 0	$ 15.43
Total cost of acquired shares (in millions)	$ 0	$ 13	$ 25	$ 25	$ 0	$ 63

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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