Note 8 - Earnings Per Share - Reconciliation of the Numerators and Denominators of the Earnings per Share Calculations (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net income available to common stockholders - Numerator basic and diluted	$ 71	$ 58
Weighted-average common shares outstanding - Basic (in shares)	144.9	144.2
Employee compensation-related shares, including stock options (in shares)	1.5	0.6
Weighted-average common shares outstanding - Diluted (in shares)	146.4	144.8