Note 18 - Income Taxes (Details Textual) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Apr. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Income Taxes [Line Items]
Operating Loss Carryforwards			$ 2,068
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration			856
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration			1,212
Deferred Tax Assets, Tax Credit Carryforwards, Foreign			358	$ 355
Accumulated Deferred Investment Tax Credit			$ 42
Operating Loss Carryforwards Limitations Minimum Ownership Change Percentage			50.00%
Operating Loss Carryforwards Limitations Ownership Change Period			3 years
Provision for tax on undistributed earnings including foreign withholding tax			$ 22	19
Deferred Tax Assets, Valuation Allowance			1,112	821
Income Tax Examination, Penalties and Interest Accrued			14	14
Uncertain Tax Benefits			22	20
Minimum [Member]
Schedule Of Income Taxes [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible			0
Maximum [Member]
Schedule Of Income Taxes [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible			5
Valuation Allowance of Deferred Tax Assets [Member]
Schedule Of Income Taxes [Line Items]
Provision associated with establishment of valuation allowance on deferred tax assets		$ 167		19
Foreign Tax Authority [Member]
Schedule Of Income Taxes [Line Items]
Deferred Tax Assets, Valuation Allowance			374	168
Deferred Tax Assets, Net of Valuation Allowance			364	322
Liability for Uncertain Tax Positions, Current				3
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued				3
Unrecognized tax benefits, settlements paid	$ 4			2
Domestic Tax Authority [Member]
Schedule Of Income Taxes [Line Items]
Deferred Tax Assets, Valuation Allowance			738	653
Deferred Tax Assets, Net of Valuation Allowance			717	$ 633
Domestic Tax Authority [Member] | IRS [Member]
Schedule Of Income Taxes [Line Items]
Liability for Uncertain Tax Positions, Current			$ 41