Note 7 - Income Taxes - Tax Effects of Temporary Differences and Carryforwards of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss and tax credit carryforwards	$ 281	$ 375
Other assets	232	200
Research and development capitalization	280	81
Asset impairments and restructuring reserves	41	30
Postretirement medical and life benefits	102	154
Other accrued liabilities	311	354
Other employee benefits	346	329
Gross deferred tax assets	1,593	1,523
Valuation allowances	(166)	(138)	$ (167)	$ (215)
Total deferred tax assets	1,427	1,385
Intangible and other assets	(108)	(103)
Fixed assets	(289)	(300)
Finance leases	(200)	(174)
Total deferred tax liabilities	(597)	(577)
Net deferred tax assets	$ 830	$ 808