XML 55 R40.htm IDEA: XBRL DOCUMENT v3.20.4
Note 1 - Description of Business and Summary of Significant Accounting Policies - Trade Revenue and Expense (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Trade revenue $ 5 $ 8 $ 3
Trade expense (5) (8) (3)
Net trade income (loss) $ 0 $ 0 $ 0