Note 20 - Weighted-average Asset Allocation By Assets Category (Details)	Dec. 31, 2020	Dec. 31, 2019
Major US Plans [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	100.00%	100.00%
Major US Plans [Member] | Equity Securities [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	10.00%	10.00%
Major US Plans [Member] | Equity Securities [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	5.00%
Major US Plans [Member] | Equity Securities [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	15.00%
Major US Plans [Member] | Debt Securities [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	42.00%	44.00%
Major US Plans [Member] | Debt Securities [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	35.00%
Major US Plans [Member] | Debt Securities [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	45.00%
Major US Plans [Member] | Real Estate [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	1.00%	1.00%
Major US Plans [Member] | Real Estate [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	0.00%
Major US Plans [Member] | Real Estate [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major US Plans [Member] | Cash and Cash Equivalents [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	2.00%	1.00%
Major US Plans [Member] | Cash and Cash Equivalents [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	0.00%
Major US Plans [Member] | Cash and Cash Equivalents [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major US Plans [Member] | Global Balanced Asset Allocation Funds [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	14.00%	15.00%
Major US Plans [Member] | Global Balanced Asset Allocation Funds [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major US Plans [Member] | Global Balanced Asset Allocation Funds [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	20.00%
Major US Plans [Member] | Other [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	31.00%	29.00%
Major US Plans [Member] | Other [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	25.00%
Major US Plans [Member] | Other [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	35.00%
Major Non-U.S. Plans [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	100.00%	100.00%
Major Non-U.S. Plans [Member] | Equity Securities [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	5.00%	5.00%
Major Non-U.S. Plans [Member] | Equity Securities [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	0.00%
Major Non-U.S. Plans [Member] | Equity Securities [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major Non-U.S. Plans [Member] | Debt Securities [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	33.00%	31.00%
Major Non-U.S. Plans [Member] | Debt Securities [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	25.00%
Major Non-U.S. Plans [Member] | Debt Securities [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	35.00%
Major Non-U.S. Plans [Member] | Real Estate [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	2.00%	2.00%
Major Non-U.S. Plans [Member] | Real Estate [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	0.00%
Major Non-U.S. Plans [Member] | Real Estate [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major Non-U.S. Plans [Member] | Cash and Cash Equivalents [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	2.00%	2.00%
Major Non-U.S. Plans [Member] | Cash and Cash Equivalents [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	0.00%
Major Non-U.S. Plans [Member] | Cash and Cash Equivalents [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major Non-U.S. Plans [Member] | Global Balanced Asset Allocation Funds [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	5.00%	5.00%
Major Non-U.S. Plans [Member] | Global Balanced Asset Allocation Funds [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	0.00%
Major Non-U.S. Plans [Member] | Global Balanced Asset Allocation Funds [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	10.00%
Major Non-U.S. Plans [Member] | Other [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Asset allocations	53.00%	55.00%
Major Non-U.S. Plans [Member] | Other [Member] | Minimum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	50.00%
Major Non-U.S. Plans [Member] | Other [Member] | Maximum [Member]
Weighted Average Asset Allocation By Assets Category [Line Items]
Target asset allocations	60.00%