Financial Instruments and Fair Value Measurements, Market risks, commodity prices and foreign currency rates (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Cash and Cash Equivalents, at Carrying Value [Abstract]
Amount of marketable securities classified as cash and cash equivalents	$ 885		$ 389
Foreign Currency [Abstract]
Foreign currency gain (loss)	$ (7)	$ 11

Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration