Note 3 - Stock-based Compensation - Stock-based Compensation (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Stock options	$ 4	$ 4
Retention awards	18	22
Total stock-based compensation, before tax	28	30
Excess income tax benefits from equity compensation plans	6	17
Employee Stock [Member]
ESPP	$ 6	$ 4

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of noncash expense for option under share-based payment arrangement.

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