Note 5 - Earnings per Common Share (Details Textual) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
		Apr. 08, 2021	Jun. 30, 2021		Dec. 31, 2020	Apr. 05, 2021	Jan. 16, 2021
Stock Redeemed or Called During Period, Value	[1]		$ 1,503
Retained Earnings [Member]
Stock Redeemed or Called During Period, Value		$ 803	$ 803	[1]
Series A Convertible Preferred Stock [Member]
Preferred Stock, Convertible, Shares Issuable (in shares)							115,000,000
Converted from Preferred Stock [Member]
Common Stock, Shares, Outstanding, Ending Balance (in shares)		80,000,000				80,000,000
Conversion of Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)					2,300
Conversion of Stock, Shares Issued (in shares)		115,000,000
Conversion of Preferred Stock into Common Stock [Member] | Samsung [Member]
Stock Repurchased and Retired During Period, Shares (in shares)		35,000,000

[1] Refer to Note 4 (Earnings (Loss) per Common Share) and Note 12 (Shareholders' Equity) to the consolidated financial statements for additional information.