Note 13 - Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Equity Securities, Unrealized Gain	$ 33
Certificates of Deposit [Member]
Debt Securities, Cost	21	$ 21	$ 19
Debt Securities, Unrealized Gain	0	0	0
Debt Securities, Fair Value	21	21	19
Common Stock [Member]
Equity Securities, Cost	16	16	0
Equity Securities, Unrealized Gain		33	0
Available-for-sale securities	$ 49	$ 49	$ 0

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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